Updated March 5, 2016 at 12:05 CET: Pope Francis has condemned the "diabolical violence" of Friday's deadly attack on a nursing home in Yemen, acknowledging in a special way the four Missionaries of Charity sisters who were killed during the siege.

"His Holiness Pope Francis was shocked and profoundly saddened to learn of the killing of four Missionaries of Charity and twelve others at a home for the elderly in Aden," reads the telegram, released Saturday and signed by Vatican Secretary of State Cardinal Pietro Parolin.

The Pope "sends the assurance of his prayers for the dead and his spiritual closeness to their families and to all affected from this act of senseless and diabolical violence," the message reads.

"He prays that this pointless slaughter will awaken consciences, lead to a change of heart, and inspire all parties to lay down their arms and take up the path of dialogue."

Pope Francis called for those involved in the the nation's ongoing conflict "to renounce violence, and to renew their commitment to the people of Yemen, particularly those most in need," who the Missionaries of Charity and collaborators "sought to serve."

"Upon everyone suffering from this violence, the Holy Father invokes God's blessing, and in a special ways he extends to the Missionaries of Charity his prayerful sympathy and solidarity."

Original story continues:

At least 16 people are dead after two gunmen attacked a Missionaries of Charity convent and nursing home for elderly and disabled persons in Aden, the provisional capital of Yemen, on Friday.

Four of the victims were sisters of the Missionaries of Charity, the community founded by Blessed Mother Teresa. They have been identified by the Apostolic Vicariate of Southern Arabia as Sr. Anselm from India, Sr. Margherite from Rwanda, Sr. Reginette from Rwanda, and Sr. Judith from Kenya.

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A March 4 statement from the Apostolic Vicariate of Southern Arabia stated that Bishop Paul Hinder has "expressed his shock at the incident and prayed that the Lord may accept the sacrifice of these sisters and convert it into a sacrifice for peace."

The convent's superior is unhurt and in police custody, the vicariate stated.

Fr. Tom Uzhunnalil, a Salesian priest from India who had been staying with the sisters since his church was attacked and burned last September, was abducted from the chapel, a source told CNA. Agenzia Fides reported that he has been missing since the attack.

Other victims of the attack included volunteers at the home, at least five of whom were Ethiopian. Many were Yemenis. The nursing home had around 80 residents, who were unharmed.

The gunmen gained entry to the Missionaries of Charity home by telling the gatekeeper their mothers were residents, The Associated Press reported.

"On entering inside, (they) immediately shot dead the gatekeeper and started shooting randomly," Vikas Swarup, the spokesman of India's External Affairs Ministry, told the agency.

Khaled Haidar told the AP that when he arrived on the scene he saw that each victim, including his brother Radwan, had been handcuffed and shot in the head.

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The Apostolic Vicariate of Southern Arabia said the Missionaries of Charity have been present in Yemen since 1973 after the then Government of North Yemen formally invited them to care for the sick and elderly. The home in Aden has been open since 1992.

Three Missionaries of Charity were killed by a gunman in Al Hudaydah, 280 miles northwest of Aden, in 1998.

Yemen is in the midst of a civil war that began in March 2015. That month Houthi rebels, who are Shia Muslims, took over portions of Yemen seeking to oust its Sunni-led government.

Saudi Arabia, which borders Yemen's north, has led a coalition backing the government. Both al-Qaeda and the Islamic State have set up strongholds in the country amid the power vacuum.

The civil war has killed more than 6,000 people, according to the United Nations.

So far no group has claimed responsibility for the attack on the Missionaries of Charity home.