New Delhi/Kolkata, Mar 05 (ANI): Mother Teresa's Missionaries of Charity expressed its condolences over killing of four Indian Christian nuns, who died in a militant attack on an old-age home in the Yemeni port of Aden. Four gunmen, who first told the guard they have come to meet their mother, stormed into the old-age home with rifles and opened fire. Sunita Kumar, spokesperson of the Missionaries of Charity, said an Indian nun, Sister Sally, survived as the attackers could not locate her. The dead included two Yemeni women working at the facility, eight elderly residents and a guard. The motive of the gunmen was not immediately known. They fled after the attack.