In the wake of the pope’s recent comments about the Prophet Mohammed — and his subsequent apology for them — the city’s police department is heightening security around Catholic churches in all five boroughs.

The pope said Friday that the prophet’s teachings are evil, referring in particular to “his command to spread by the sword the faith he preached.” His comments sparked a wave of violence around the world, including the murder of an Italian nun in Mogadishu, Somalia, on Saturday and riots in Iraq.

Although there have been no specific threats against New York’s Catholic churches, a spokesman for the police department, Deputy Commissioner Paul Browne, said officers are taking “extra precaution because of incidents elsewhere.” Since Sunday, patrol officers have been guarding churches.

Some churches are also ratcheting up their security internally. St. Patrick’s Cathedral, a center of American Catholicism and the seat of the Archbishop of New York, is implementing security increases quietly in an effort to avoid alarming its congregants, according to a source inside the church who asked not to be identified. The source said most of the Catholic churches in the city are doing the same thing. The cathedral’s communications department declined to comment on the details of the increased security measures.

In addition, a Long Island Catholic high school posted police officers at three of its four entrances after receiving an a threat through the Web site MySpace.com.

Sean Dolan, a spokesman for the Diocese of Rockville Center, which runs the school, told the Associated Press that the threat mentioned the use of a gun and was made was made against faculty, students, and school officials. Mr. Dolan declined to say whether the threat had any connection to the pope’s comments or the weekend violence due to the fact that there is an ongoing investigation under way to discover the identity of the individual who made the threat.