BRUSSELS, Belgium — Roman Catholic leaders in Turkey held an emergency summit yesterday to discuss threats against Pope Benedict should his planned visit go ahead in November.

Clergy living in Turkey have reported a sharp increase in anti-Catholic attacks in recent months.

A priest was murdered in the Turkish Black Sea city of Trabzon last February, and two more have been seriously injured in stabbing incidents.

Catholic leaders have blamed the attacks on hard-line Turkish nationalists who want to preserve the country’s Islamic identity.

Concerns about the safety of Catholic clergy in Turkey and Benedict’s visit have been heightened following the publication of a thriller by one of Turkey’s best-selling authors whose main plot concerns an attempt to assassinate the pope.

A spokesman for the Turkish foreign ministry reiterated that the pope remains welcome after his expression of regret for hurt among Muslims for the contents of a speech delivered in Germany last week. The Vatican remains committed to the trip.

The European Union issued a robust defense of Pope Benedict’s position, warning that fundamental European freedoms were at stake. As a candidate for E.U. membership, Turkey would be expected to follow Brussel’s line.

The chief commission spokesman, Johannes Laitenberger, said: “Reactions that are disproportionate and tantamount to rejecting freedom of speech are unacceptable. Freedom of speech is a cornerstone of the E.U.’s order, as is the freedom of all religions and beliefs.”

Demonstrations continued yesterday as crowds burned an effigy of the pope in Basra, Iraq, while smaller protests were held across other cities.

The meeting of Turkish bishops and the papal nuncio in Istanbul was arranged to finalize a schedule for the pope’s visit November 29–December 1 visit.

Apart from discussing the recent attacks on Catholic clergy, the bishops also expressed their concern about the timing of publication of the novel: “Assassinating the Pope: Who Will Kill Benedict XVI in Istanbul?” The novel by Yucel Kaya, one of Turkey’s best-selling writers, is a conspiracy-filled plot based loosely on Dan Brown’s bestseller, “The Da Vinci Code.” Secretive organizations including Opus Dei and the Turkish Secret Service, team up to brainwash a female Italian journalist into murdering the pope during his first visit to Turkey.

The Vatican’s representative in Istanbul, Monsignor Louis Pelatre has expressed deep alarm that the work may inspire an attack. He said: “All this is sad and worrying.”

Monsignor Antonio Lucibello, the papal nuncio, called on the Turkish authorities to guarantee Benedict’s safety. He said: “We are counting on the Turkish government doing its utmost to guarantee the greatest security possible for the pope, organizing his visit down to the minutest details.”