Ukraine Seeks to Skirt Political Crisis amid Tough MH17 Probe

Ukraine sought Friday to avoid a political crisis after the shock resignation of its prime minister, as fighting between the army and rebels close to the Malaysian airliner crash site claimed over a dozen more lives.

President Petro Poroshenko called on parliament to heed "cold reason" and pass a vote of confidence in the government, a day after premier Arseniy Yatsenyuk walked out in fury over the collapse of his ruling coalition.

Yatsenyuk's resignation piles on more woes for a country already struggling to cope with a chaotic situation in the rebel-controlled east, where international experts are carrying out a complex investigation into last week's downing of Malaysia Airlines flight MH17 that left 298 dead.

The grave challenges facing the country -- where the U.N. said 230,000 people have fled fighting -- go beyond its borders, as Washington accused Russian troops of firing artillery across the border on Ukrainian forces.

The United States has already accused Moscow of supplying the missile system which it believes was used by pro-Russian separatists in east Ukraine to shoot down MH17. It said late Thursday it had evidence that Russia was planning to "deliver heavier and more powerful multiple rocket launchers" to the rebels.

Both Moscow and the rebels deny having anything to do with the shooting down of the passenger airliner and have both promised to cooperate with an international probe into the disaster.

A truce has been declared in the vicinity of the vast crash site in rebel-held Grabove, where experts say some remains of the victims still lay decomposing under the sweltering summer heat more than a week after the tragedy.

Dutch authorities have said they are only sure that about 200 of the bodies have been recovered from the scene, as two more planes carrying 74 more coffins left Ukraine for the Netherlands.

To secure the debris scene, the Netherlands, which is leading the probe after losing 193 citizens in the crash, said it was sending 40 police to the site.

Australia, which lost 28 citizens in the crash, said it already has 90 police in Europe ready to deploy and that it also plans to send troops.

"This is a humanitarian mission with a clear and simple objective, to bring them home," Prime Minister Tony Abbott said. "All we want to do is to claim our dead and to bring them home."

The government's offensive to regain control of Ukraine's eastern industrial heartland was given a boost Friday when its forces took the strategically-important city of Lysychansk.