Two masked assailants attacked a Roman Catholic church in Istanbul during Sunday services, killing one person, Turkish officials said.

According to a statement posted on X, formerly Twitter, by Interior Minister Ali Yerlikaya, the armed assailants attacked the Santa Maria Church in the Sariyer district of the city at 11.40am local time.

He did not specify what kind of weapons were used or whether anyone else was injured.

Mr Yerlikaya condemned the attack and said authorities are working on capturing the assailants.

An investigation is under way.

Speaking to reporters, Istanbul Mayor Ekrem Imamoglu offered his condolences and support for religious minorities in the city, which, like Turkey, as a whole is primarily Muslim.

“There are no minorities in this city or this country. We are all actual citizens,” he said.

Speaking to the Associated Press, the victim’s nephew identified the man who died as Tuncer Cihan. He noted that the target was the church and not his uncle.

“He was a mentally disabled individual who had no connection to politics or (criminal) organisations. He went there on an invitation and was a victim of fate,” Cagin Cihan said.

Santa Maria is run by missionary Franciscan friars from Italy sent on a mission of ecumenical dialogue.

In remarks to the public in St Peter’s Square on Sunday, Pope Francis noted the attack.

“I express my closeness to the community of (the church) in Istanbul, which during the Mass suffered an armed attack with one dead and some wounded,” the pontiff said.

Italy’s foreign minister, Antonio Tajani, said his ministry is following the situation along with the Italian embassy in Ankara and the consulate in Istanbul.

“I express my condolence and firm condemnation for the vile attack on Santa Maria Church,″ he wrote on X.

He added that “I am certain that the Turkish authorities will arrest those responsible.”