Hospitals in Ukraine's eastern Donetsk region were jammed with victims on Monday in the wake of a string of deadly mine accidents, the Interfax news agency reported, according to dpa. City clinics were treating 156 miners injured in one of three blasts taking place in the Zasyadko mine over the last two weeks. Ukrainian Prime Minister Viktor Yanukovich left the capital Kiev early Monday morning to travel to Donetsk by plane. Yanukovich, a native of the Donetsk region, visited the site of the explosions in the heart of Ukraine's coal mining territory, and met with local officials. Donetsk health providers were doing what they could to give the injured aid, but at the present accident rate the local medical system could become overtaxed, Ihor Krol, a Donetsk health official, said. The most recent explosion in the Zasyadko pit, on Saturday, killed five rescue workers and left dozens of emergency personnel and coal miners injured. A November 18 blast killed 101 in Ukraine's worst-ever coal mining accident. The bodies of ten victims are still buried more than a kilometre underground, according to the report. A December 1 explosion caused no fatalities but put 50 into hospital. From January to July of this year, more than 250 Ukrainian miners died in accidents and nearly 6,000 were injured. Methane gas accumulation and poor safety procedures during coal mining are the most likely cause of the first two accidents, while the last, on Saturday, was linked to emergency workers' efforts to clear damaged shafts, Ukraine's Minister of Coal Mining ,Serhy Tulub, said. Ukraine's Zasyadko coal mine, in operation for more than a century, is among the world's most dangerous. A May 24, 1999 explosion in the mine killed 50 miners, and a August 19 2001 blast left 55 dead.