“In connection with the tragedy which happened on January 13, 2015, at the checkpoint near Volnovakha town which resulted in numerous casualties, January 14 was declared a day of mourning,” the statement posted on the official website of the Donetsk administration said.
On Tuesday, it was reported that a passenger bus was shelled near Volnovakha south of the city of Donetsk. Initially the shelling left 10 dead and 17 injured at the scene, but on Wednesday another two people were reported to have died at the hospital.
Ukrainian President Petro Poroshenko accused independence supporters from the self-proclaimed Donetsk People's Republic (DPR) of the shelling. The DPR denied the accusations, calling them a provocation by Kiev, further stating that DPR artillery was located more than 50 kilometers (31 miles) away, and incapable of reaching the town or its neighborhoods.
On Tuesday, the United Nations Security Council condemned the attack in the strongest terms, and called for an impartial investigation into the case and stressed that the perpetrators must be brought to justice.
The military conflict in southeastern Ukraine began in April, as Kiev launched a military operation against local independence supporters, who refused to accept a new government which they claim came to power in the result of a coup.
Despite the ceasefire agreement the fighting continues, with both sides accusing each other of numerous violations.
According to the UN humanitarian agency OCHA, over 4,800 people have been killed in the violence in eastern Ukraine since April 2014.