ROVE CITY, Ohio — On a recent Saturday in a church fellowship hall here, evangelical Christians from several states gathered for an all-day seminar on how to woo Muslims away from Islam. The teacher urged a kindly approach: always show Muslims love, charity and hospitality, he said, and carry copies of the New Testament to give as gifts. The students, scribbling notes, included two pastors, a school secretary and college students who said they hoped to convert Muslims in the United States, or on mission trips abroad.

But although the teacher, an evangelical preacher from Beirut, stressed the need to avoid offending Muslims, he projected a snappy PowerPoint presentation showing passages from the Koran that he said proved Islam was regressive, fraudulent and violent.

"Here in the Koran, it says slay them, slay the infidels!" said the teacher, who said he did not want to be identified because being a missionary to Muslims put his life at risk. "In the Bible there are no words from Jesus saying we should kill innocent people."

At the grass roots of evangelical Christianity, many are now absorbing the antipathy for Islam that emerged last year with the incendiary comments of ministers. The sharp language, from religious leaders like Franklin Graham, Jerry Falwell, Pat Robertson and Jerry Vines, the former president of the Southern Baptist Convention, has drawn rebukes from Muslims and Christian groups alike. Mr. Graham called Islam "a very evil and wicked religion, and Mr. Vines called Muhammad, Islam's founder and prophet, a "demon-possessed pedophile."

In evangelical churches and seminaries across the country, lectures and books criticizing Islam and promoting strategies for Muslim conversions are gaining currency. More than a dozen recently published critiques of Islam are now available in Christian bookstores. Arab International Ministry, the Indianapolis group that led the crash course on Islam here, claims to have trained 4,500 American Christians to proselytize Muslims in the last six years, many of those since the 2001 terrorist attacks.

The oratorical tone of these authors and lecturers varies, but they share the basic presumption that the world's two largest religions are headed for a confrontation, with Christianity representing what is good, true and peaceful, and Islam what is evil, false and violent. The criticism is coming predominantly from evangelicals, who belong to many independent churches and Christian denominations, including the Southern Baptist Convention.

Evangelicals have always believed that all other religions are wrong, but what is notable now is the vituperation. "The Koran's good verses are like the food an assassin adds to poison to disguise a deadly taste," writes Don Richardson, a well-known missionary who worked in Muslim countries, in "Secrets of the Koran" (Regal Books, 2003). "Better to find the same food, sans poison, in the Bible." This month, he is scheduled to speak on Islam at churches in five American cities.

Most of the authors and teachers preach a corollary of the Christian dictum to "love the sinner and hate the sin." They assert that while the vast majority of Muslims are not evil, they have been deceived by a diabolical religion based on a flawed scripture that can never bring them salvation.

Akbar Ahmed, chairman of the Islamic studies department at American University, said he grew up attending Catholic and Protestant missionary schools in Pakistan, but never heard a negative word about Islam from the missionaries. Now, he said, the new hostility to Islam and, in particular, the insults to the prophet Muhammad have outraged the Muslim world. "The whole range of Muslims, from orthodox to liberal secularists, are all lined up against these attacks coming from the American evangelists," said Mr. Ahmed, the author of a new book "Islam Under Siege: Living Dangerously in a Post-Honor World" (Polity Press). "Unwittingly, these evangelists have unleashed a consolidation of sentiments for Islam. Even the most moderate Muslims have been upset by this." The push for conversions may backfire for the evangelists, he said, since Muslims who may have been open to the missionaries' presence feel their honor has been insulted.

In interviews, evangelical authors and lecturers said their work did not denigrate Islam as much as share the truth about Christianity. Ergun M. Caner, raised a Muslim by his Turkish family, converted to Christianity as a teenager and wrote, with his brother Emir, "Unveiling Islam: An Insider Look at Muslim Life and Beliefs" (Kregel Publications), which has sold more than 100,000 copies. "I am more interested in apologetics than polemics," said Mr. Caner, now a professor of theology and church history at The Criswell College. "Apologetics is defending your faith, and polemics is critiquing others. A Muslim has the right to to worship Allah, and I have a right to stand in front of that mosque and tell them that Jesus saves. That's the hope for Iraq, the hope for Afghanistan."

Evangelical scholars and leaders cite several reasons for their quickening interest in Islam: the American defeat of a major Muslim nation, Iraq, which may open it to Christian missionaries, while other Muslim nations remain closed; the 2001 terrorist attacks, which led many Americans to see Islam as a global threat; the greater numbers and visibility of Muslims in the United States, and the demise of Communism, once public enemy No. 1 for many evangelical organizations. "Evangelicals have substituted Islam for the Soviet Union," said the Rev. Richard Cizik, vice president for governmental affairs of the National Association of Evangelicals, which represents 43,000 congregations. "The Muslims have become the modern-day equivalent of the Evil Empire."

The National Association of Evangelicals called on Christian leaders this month to temper their anti-Islam oratory, saying it had been unhelpful to interfaith relations, and dangerous to Christians spreading the gospel to Muslims. While some evangelical leaders welcomed the criticism, others bristled and said that it was not the Christians but the Muslims who must stop the hate-speech.

Historians note that enmity between Christianity and Islam dates as far back as the Crusades, the fall of Byzantium and the reconquest of Spain. "Keep in mind that Islam is the only religious tradition that has ever threatened the existence of Christianity," said Charles Kimball, chairman of the religion department at Wake Forest University in Winston-Salem, N.C., and author of the book "When Religion Becomes Evil" (Harper San Francisco, 2002). "That's deeply woven into our subconscious, into Western literature and culture, and so this image of an Islamic threat taps into a notion that's there already."

The conservative evangelical approach to Islam is in stark contrast with the "interfaith understanding" approach of many Orthodox, Roman Catholic and mainline Protestant churches like the Methodists, Episcopalians and Lutherans. Since 9/11, local churches in these denominations began inviting Muslims to explain their faith at a flurry of interfaith events and dialogue sessions.

"God calls all of us to have an open mind and an open heart," said the Rev. Robert Edgar, general secretary of the National Council of Churches, which represents many Protestant and Orthodox denominations. "And many of the people who are part of the National Council of Churches believe that if judgment is to be made it needs to be made by God and not by those of us who have divided ourselves up around a particular ideology." These churches acknowledge theological differences between Christianity and Islam, but stress the common roots and essential compatibility. They teach that Muslims are monotheists, "Allah" is simply Arabic for God, and both faiths share Abraham as patriarch.

But for many of the evangelical experts on Islam, these notions are simplistic whitewash to paint over a real theological divide. At the daylong seminar in the fellowship hall of Southwest Grace Brethren Church, just outside Columbus, the teacher drew on his own life experience as evidence of Islam's evils. While President Bush and others have depicted Islam as a peaceful religion that has been "hijacked" by extremists, the teacher said he knew better than to believe that.

He spoke of a childhood friend in Beirut who joined the Hezbollah terrorist network and showed off his victims' severed ears. Another friend, he said, was threatened with death by his father when he converted to Christianity. (The teacher did not mention the Phalangist Christian militias that helped stoke Lebanon's civil war.)

He did not tell the class who he was, and his mysteriousness reinforced his message that Christian missionaries face danger in Muslim nations. At least six have been killed since Sept. 11, 2001. "You can tell me Islam is peaceful, but I've done my homework," he said, reeling off a list of Koranic citations. "From the beginning of Islam, the sword brought results faster than words."

Some of what he taught would be accepted by most theologians: Muslims reject the Christian concept of a Trinitarian God — the Father, the Son and the Holy Ghost. Muslims respect Jesus as a prophet, but do not accept the Christian belief that he is the son of God. But he intermingled accepted facts with negative accounts of Islamic teaching, history and traditions. The pilgrimage to Mecca, he said, is a dangerous event at which people are killed every year. Communal prayers each Friday are "a day of rage," he said. And Muslims even pray differently than Christians, he said. "Muslims pray to get points," he said, "not to communicate with God." Group prayer on Fridays is for "extra points," he said.

Pat McEvoy, a secretary at a high school in Columbus, said she had known very little about Islam before the seminar. Her school has an influx of students from Somalia, and as she walked through the hallways she regarded these immigrants as "a virtual mission field." She said she felt an obligation to save them from an eternity in Hell. "If I had the answer for cancer, what sort of a human would I be not to share it?" Ms. McEvoy said.

The teacher concluded by giving the students tips on what to do and not to do to reach Muslims: Don't approach them in groups. Don't bring them to your church, because they will misunderstand the singing and clapping as a party. Do invite them home for a meal. Do bring them chocolate chip cookies. Do talk about how, in order to get saved, they must accept Jesus. "Our job," he said, "is not to make the Muslim a Christian. Our job is to show them the love of Christ."