US leads military drills in Ukraine while fighting continues in east

US-led military exercises involving 15 countries were set to begin in Ukraine yesterday, as fighting rumbled on in the restive east between government forces and pro-Russian rebels in violation of a ceasefire.

Heavy fighting erupted around the rebel stronghold of Donetsk in eastern Ukraine on Sunday, piling further pressure on a precarious nine-day-old truce between the government and separatist fighters.

Large clouds of thick black smoke billowed over the industrial city as the boom of sustained shelling and the rattle of automatic gunfire rang out throughout the day.

Donetsk council said there had been civilian casualties and described the situation in the city as "critical" but gave no further information.

Kiev accused the rebels of jeopardising the truce by intensifying their attacks on government positions in eastern Ukraine, the scene of five months of deadly combat.

While Kiev and the West accuse Russia of playing a role in the rebellion in the east, soldiers from the 15 nations were to begin military exercises dubbed "Rapid Trident 14" near Lviv in the west of the country.