A Dutch priest who had steadfastly refused to leave the besieged Syrian city of Homs was assassinated by masked gunmen Monday, a killing that robbed Syria of one of its most high-profile interfaith figures.

The Rev. Frans van der Lugt, 75, a Jesuit who had lived in Syria for almost 50 years, was shot in the head in the garden of his monastery in a rebel-held area, according to colleagues and Syrian opposition fighters.

It was unclear who carried out the killing, as rebels and the government blamed each other. But residents said tensions have been high over a possible cease-fire agreement that would evacuate more civilians from rebel-held areas of the city, similar to agreements brokered in the Damascus suburbs in recent months. Extremist rebel groups had objected to further evacuations, said Khaled Erksoussi, head of operations at the Syrian Arab Red Crescent.

The priest was “a Syrian among Syrians” who refused to abandon his adopted people even when it meant risking his own life, Dutch Foreign Minister Frans Timmermans said. In a statement, the Vatican called van der Lugt a “man of peace” who wanted to remain faithful to the people to whom he had dedicated his spiritual service.

Van der Lugt had repeatedly called for a solution to end the suffering of residents in besieged areas of Homs, which has been cut off from food supplies by a government siege and is regularly bombarded. His monastery sat in the Bustan al-Diwan area of the Old City, one of the worst-hit districts in a city that has been crippled by the three-year-old Syrian war, and one of the few still held by the opposition.

Destruction and hardship plague the residents who remain in the embattled city of Deraa, considered to be the cradle of the uprising. (Reuters)

Humanitarian workers said van der Lugt worked tirelessly to negotiate humanitarian access to the area ahead of the evacuation of 1,400 people by the United Nations in February, when Western-backed peace talks in Geneva turned the international spotlight onto Homs.

“He was one of the very few people who could cross the front lines in Homs,” Erksoussi said. “Whoever killed him is hindering any effort for peace. Whoever killed him knew he had good relations with almost everybody.”

Van der Lugt was shot in the head in a “premeditated act,” the Rev. Ziad Hillal, another Jesuit who lived with him, said in an interview with Vatican Radio. A video posted online showed the priest’s robed body being laid in a coffin.

The rebel military council in Homs said in a statement that it had “appreciation and respect” for the priest’s work and valued his commitment to the people of Homs, and it accused the government of being behind the killing. The Syrian state news agency blamed “terrorists.”

A trained psychotherapist, van der Lugt moved to Syria in 1966 after two years studying Arabic in Lebanon. He was known for his interfaith work, setting up hiking trips in the 1980s aimed at bringing Muslims and Christians together. He later established al-Ard, a spiritual center that endeavored to fight rural depopulation and also housed children with mental disabilities.

“He was always pushing us to move forward past our difference and to dream and coexist as Syrians,” said Oula Abdulhamid, 27, the daughter of a prominent Syrian dissident, who had known the priest since childhood and described him as a “grandfather” to her. “Because of him, I learned so much about my country.”

Just 24 Christians were left in his congregation, but he refused to leave them, according to friends and residents. He also took in displaced families, residents and activists said.

In a video clip released this year, van der Lugt described the harsh conditions Muslims and Christians were enduring.

“We suffer from a lot of problems,” he said. “The biggest of which is hunger. There is nothing harder than seeing parents in the street looking for food for their children.”

Since the breakdown of international peace talks, the siege on rebel-held areas of Homs has resumed. Aid deliveries and evacuations are stalled, leaving an estimated 1,000 civilians facing hunger.

“He said he would be the last person to leave and would suffer the same fate as his people,” said Abdulhamid, who is now based in the United States. “And people are dying there, and now he’s dead too, murdered.”

Ahmed Ramadan contributed to this report.