KOLKATA, India -- A charity group established by Mother Teresa said Monday an Indian Catholic priest was abducted by militants when they attacked a retirement home in southern Yemen last week, killing 16 people including four nuns.

Missionaries of Charity spokeswoman Sunita Kumar said in Kolkata that Father Tom Uzhunnalil was handcuffed and taken away by the attackers when they stormed the retirement home in Aden.

They destroyed the chapel and the center, Kumar said.

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On Sunday, Pope Francis said the four nuns killed in an attack on a home for the elderly in Yemen are modern-day martyrs and victims of indifference.

Francis, who has apparently been deeply moved by the incident, told the faithful Sunday that the nuns "gave their blood for the Church" and that they were not only victims of the attackers but also of "this indifference of globalization."

People gather at the site of a car bomb attack in Yemen's southern port city of Aden January 5, 2016. Three senior southern Yemeni officials survived a suicide car bomb attack on their convoy in Aden and a subsequent gun battle that killed three of their guards on Tuesday, a government spokesman and security sources said. Nasser Awad/Reuters

Indian External Affairs Ministry spokesman Vikas Swarup said there was no information about the priest's current location or status.

After they entered the retirement home, the gunmen moved from room to room, handcuffing their victims before shooting them in the head. Kumar said two of the killed Catholic nuns were from Rwanda and the other two were from India and Kenya.

The Indian embassy in Yemen was closed but its office in Djibouti was trying to ascertain the whereabouts of the Indian priest to secure his release. "We will spare no efforts to rescue Father Uzhunnalil," Indian External Affairs Minister Sushma Swaraj said on Twitter.

There were around 80 residents at the home at the time of the attack. Missionaries of Charity nuns also came under attack in Yemen in 1998, when gunmen killed three nuns in the Red Sea port city of Hodeida.

Aden descended into lawlessness after a Saudi-led coalition recaptured the city from Shiite Houthi rebels last summer.

Yemen's civil war has split the country in two. The northern region, where Shiite rebels are in control, has been struck by an extensive air campaign by a Saudi-led coalition. The southern region, which is controlled by the internationally recognized government backed by Saudi Arabia, is suffering from a power and security vacuum.

The Islamic State group and Yemen's al-Qaida affiliate have exploited the lawlessness and created safe havens in the south. Al-Qaida controls several southern cities while IS has claimed responsibility for a wave of deadly attacks in Aden, including a suicide bombing that killed the city's governor and several assassination attempts on top officials.