City bus shelled in eastern Ukraine

Local authorities in Donetsk, a pro-Russian separatist stronghold in eastern Ukraine, said at least seven people have been killed after an artillery shell hit a city bus on Thursday morning. The strike followed a night of intense fighting at the city's main airport and coincided with diplomatic talks involving Ukraine and Russia.

The explosion instantly killed a number of passengers and blew out the windows of a nearby building. A rebel official at the site said up to 10 people may have been killed.

Fighting between Ukrainian government troops and separatist forces surged after the New Year after a month of relative tranquillity after a cease-fire was declared in early December.

Residential areas are frequently struck as a result of artillery duels between the warring sides. It was unclear Thursday who was responsible for the attack.

Ukrainian forces have all but abandoned the Donetsk airport after months of bitter battles, although military officials continue to insist they hold part of the terminal.

The Defense Ministry said Thursday that six soldiers died over the previous day of fighting for the airport, which lies on the northern edge of the Russian-backed separatists' stronghold.

Russian television reporters on Wednesday toured the airport building and showed the bodies of killed Ukrainian soldiers.

Modest progress appeared to have been made late on Wednesday in talks on the crisis in Berlin involving Ukraine, Russia, Germany and France.

German Foreign Minister Frank-Walter Steinmeier said foreign ministers agreed to a demarcation line between pro-Russian fighters and Kiev's forces from which both sides would begin withdrawing heavy weapons.

A joint statement issued by the German foreign ministry said tangible progress on implementation of a 12-point protocol drawn up in Minsk, Belarus, in September had to be achieved before a summit was possible.

Fighting in eastern Ukraine has killed more than 4,700 people since April, according to U.N. estimates.

Wire services