Nine Ukrainian soldiers have been killed in the eastern city of Donetsk and scores more wounded during fighting at the city’s airport, according to the Ukrainian National Security and Defense Council Information Center.

Three civilians were also killed overnight by shelling.

It is the heaviest fighting in the area since a ceasefire was signed earlier in September.

Ukrainian military spokesman, Andriy Lysenko said: “For the last 24 hours our militaries have repelled two very strong attacks. During the evening attack, a Ukrainian Armed Personnel Carrier with the crew and paratroopers was destroyed by a direct tank hit. A fierce battle has started, and our paratroopers encountered losses.”

Meanwhile, another apparent mass grave has been discovered near Donetsk in the village of Nizhny Krynka. The new site does not appear to have been verified by international observers and its existence is denied by Ukrainian authorities.

The site was located days after an OSCE mission confirmed the discovery of three mass burial sites in Slovyansk. The Ukrainian army and separatists have both accused each other of the killings.