The death toll from an explosion at a coal mine in eastern Ukraine has risen to 32, according to officials.

The self-appointed government in rebel-held Donetsk added that one person remains unaccounted for.

The blast occurred before dawn yesterday more than 3,200ft underground at the Zasyadko mine in Donetsk, where bitter fighting has raged for almost a year between Russian-backed separatists and Ukrainian forces.

The explosion - which happened as 230 workers were in the mine - was not caused by shelling, rebel authorities said. They blamed a combustible mixture of methane and air - a common cause of industrial mining accidents.

Zasyadko mine has a history of deadly accidents, including one in November 2007 that killed 101 workers, and two more the following month that killed 57.