ROME – Following the death of seven people, who were killed when a Russian tank destroyed the Caritas office in the Ukrainian city of Mariupol, the head of Caritas Internationalis called for an end to the violence.

“Our sadness turns into an appeal to the international community to exert every effort to bring this violence to an end, to return to dialogue, and to see a brother and sister in every person,” said Filipino Cardinal Luis Antonio Tagle.

The deadly attack was reported by Caritas-Spes Ukraine and Caritas Ukraine on April 11, but the incident itself occurred on March 15, during the worst of the Russian attacks into Mariupol, which has been besieged by Russian forces since the beginning of the war.

The city is located in southeastern Ukraine, near an area of the country occupied by Russia in 2014. Its population before the war was around 430,000 and about 120,000 are believed to remain in the city without access to food and drinking water.

Members for the Mariupol Caritas office released an account of the attack on Monday, saying that even though they could confirm the death of two Caritas accountants and five others sheltering in the office, “unfortunately, we don’t have the exact information about the people in our office at that time, so we can’t tell who was there that day.”

The Caritas Ukraine Twitter account reported that the Caritas office in Mariupol was destroyed after being “shot by a Russian tank.”

“I feel deep sadness and shock at the news of the attack that led to the loss of lives,” Tagle told Vatican News. “Caritas Internationalis expresses its profound sympathies and closeness to the families of those who lost their lives and were wounded.”

Aloysius John, the Secretary General of Caritas Internationalis, an umbrella organization that brings together over 150 national Caritas offices, said that the “dramatic news” was horrifying and shocking, and that the entire Caritas family joined in solidarity with the suffering families and “our colleagues of Caritas Ukraine who are living a tragedy.”

Tagle also addressed the hundreds of Caritas volunteers in Ukraine, extending a “word of gratitude” to all the women and men risking their lives helping others.

“You are doing a holy action, holy work,” the cardinal said. “For every good action done selflessly, you are sowing seeds of truth, justice, love, and peace that will change the world. God will make sure that your efforts will not be in vain. They will bear fruit.”

He also said that the world honors their sacrifice by praying for them and their families, because “we believe that God hears the cry of the poor and the just. We honor them by affirming the value of the service rendered by humanitarian organizations that must be respected. We honor them by praying to God and appealing to people of goodwill to think of and work for peace.”

According to the mayor of Mariupol, Vadym Boychenko, more than 10,000 civilians have died during the Russian siege of his city. He said he believed the death toll so far could surpass 20,000 and added that corpses are “carpeted through the streets.” Boychenko also claimed the Russians are using mobile crematories that will render it virtually impossible to know the true death toll of the city.