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.
The attack comes as Yemen is embroiled in a civil war that killed more than 6,000 people, according to the United Nations.
In March 2015 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.
Bishop Hinder said the attack on the Missionaries of Charity convent is proof that the war rages on, despite all attempts for negotiation.
"There are groups, especially in Aden region, who are not under control of the regular government and try to destabilize the country and to terrorize the people," he said, noting that the few remaining Catholics will soon "have no other choice than to remain as discreet as possible" and try to wait for peace to be reinstalled.
The bishop said that currently its "impossible" to give an exact number of the Catholics left in Yemen because the war makes it difficult to obtain reliable statistics.
Many of the Catholics who haven't left the country could be working in hospitals, but are unable able to reach their places of worship, which at present "are working only in a reduced way," he said.
He blamed this on "the nationwide insecurity," adding that before the war, he the estimated number of Catholics that he sent to Rome was 4,000 in all of Yemen.
However, Bishop Hinder said that he is sure "that in the meantime the number has essentially dropped."
Although the effects won't be seen immediately, the bishop said that both the sisters' sacrifice as well as our prayers "will work."
(Story continues below)
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"As Christians we believe that Golgotha is not the end, but the Risen Lord who will have the final word at the last judgment."
The bishop also said that he currently has no information on the whereabouts of Fr. Tom Uzhunnalil, a Salesian priest from India who had been staying with the sisters since his church was attacked and burned last September, and who has been missing since the Aden attack.
Fr. Uzhunnalil belongs to the Province of the Salesians of Bangalore and has been a missionary in Yemen since 2012, first in Taiz, and later in Aden at a church dedicated to St. Francis.
The Salesians have been present in Yemen for 29 years and are the only Catholic ministers in the country. Fr. Uzhunnalil was the only one left in Aden, and so collaborated closely with the Missionaries of Charity, who are the only religious congregation in the city.
Although the whereabouts of Fr. Uzhunnalil are still unclear, the Secretary of the Province of Bangalore, Fr. Valarkote Matthew, said in a March 6 communique that it seems as if Fr. Uzhunnalil "was taken away."
However, he stressed that "this still needs to be confirmed. We are trying to ascertain the facts from different sources, but we only know for sure that around half past 8:30 in the morning several members of Al-Qaeda or Daesh (ISIS) broke into the convent."