Recep Tayyip Erdogan said an investigation was launched into the vandalism in the southeastern city of Adiyaman. Interior Minister Idris Naim Sahin earlier said children were believed to be behind the marking of the houses with red paint.

The incident has strained nerves in Adiyaman since Alevi houses were similarly marked before a weeklong rampage and looting that killed more than 100 Alevis in neighboring Kahramanmaras province in 1978. Alevi houses were also marked in the same way before clashes in the central Anatolian city of Corum in 1980.

The country’s Alevi Muslims, who incorporate shamanistic traditions and do away with many customary Islamic practices, including the separation of men and women in prayer, have long faced discrimination in Turkey. They are considered heretics by many Sunni and Shia traditionalists.

“We are not the government of a certain belief or ethnic group, we are the government of all 75 million citizens,” Erdogan told a meeting of his ruling party in the Parliament. “We are the guarantor of the rights and security of all people without any discrimination.”

The tensions come ahead of a trial next week during which a court is expected to make a decision whether a statute of limitations has expired for some suspects who allegedly torched a hotel in 1993 that left 37 people dead, including many Alevis.

“The incident has seriously worried us,” said Devlet Bahceli, head of an opposition party. “It has aggravated our fears about an imminent chaos based on ethnicity.”

Senal Sarihan, the leading lawyer for the families of the victims killed in 1993 in the central Anatolian city of Sivas, called on the court to consider the attack as a crime against humanity without any deadline.

More than 30 suspects, including some 15 who fled abroad, have been sentenced to life in prison. The court in Ankara will decide on March 13 on the fate of five out of seven fugitives, two of whom have died.

“I have repeatedly said that justice that comes late has no meaning and that there should be no statute of limitations in such cases,” Culture Minister Ertugrul Gunay said Monday.

Kemal Kilicdaroglu, the leader of the main opposition party, called on the Parliament to quickly take up a proposed bill and remove the threat of statute of limitations in the case, saying “killers should not get away with it.”

Authorities had blamed the left-wing writer, Aziz Nesin, for touching off the rampage in Sivas on July 2, 1993, by flaunting his atheism and telling an audience that the age of the Qur’an had passed.

Nesin, who had published excerpts from Salman Rushdie’s novel, “The Satanic Verses” had been portrayed as the main target but he escaped unharmed.

The victims who died included Alevi poets, writers and folk singers. They had gathered to commemorate Pir Sultan Abdal, a 16th-century bard hanged for preaching rebellion against Sunni Muslim Ottoman government when the rivalry of their ancestors was crushed by Sultan Selim I.

Alevis, including both Kurds and Turks, have been a focus of interest for the European Union, which has made religious liberties a condition for Turkish membership.

They have increasingly demanded religious equality in Turkey, where state-run religious services are tailored for the Sunni majority. The Alevis also want an end to compulsory religious culture and ethics classes in schools, which they say have Sunni bias, and recognition of their houses of worship, which are denied state funding.

In the latest violence, involving Alevis, 21 people were killed in Istanbul’s low-income neighborhood of Gaziosmanpasa during four days of rioting in March 1995, when police clashed with thousands of people protesting a slaying by unidentified gunmen in a coffeehouse.