The insurgent stronghold of Lugansk in eastern Ukraine is on the verge a humanitarian catastrophe, the mayor warned Saturday, as a siege by government troops has seen water, electricity and food supplies cut off.

The hub of some 420,000 people, the second largest rebel-controlled city after Donetsk, has seen almost daily shelling claim the lives of scores of civilians as Ukraine's military tightens its grip on pro-Russian fighters hunkering down there.

Australian Prime Minister Tony Abbott Saturday welcomed the recovery of more remains from the crash site of Flight MH17 but said it would take at least another week to complete the task.

Ukrainian President Petro Poroshenko on Friday pledged the strife-torn nation would have a new parliament in place in the next few months, confirming that he intends to call long-awaited legislative polls.

"In autumn there will be a new parliament that will start on reforms," Poroshenko said in a televised interview.

Dutch and Australian experts gathered more remains from the crash site of downed flight MH17 in east Ukraine, as they scrambled to make up for lost time amid deadly clashes between government troops and pro-Russian rebels.

Seventy police investigators -- by far the largest number to reach the location so far -- finally managed to comb the scattered wreckage in the fields where the Malaysia Airlines plane was downed two weeks ago killing all 298 people on board.

The U.S. Senate approved President Barack Obama's nominee for ambassador to Moscow Thursday, a quick confirmation amid a long backlog of would-be envoys awaiting a vote.

Fourteen people were killed, including at least 10 government soldiers, in fighting overnight close to the crash site of downed Malaysia Airlines flight MH17, a Ukrainian military spokesman said Friday.

"In total it is known that 14 people died but the bodies of four of them have not been identified and could be Ukrainian soldiers or terrorists," said Oleksiy Dmytrashkivsky.

Kiev on Thursday announced a day-long halt to its deadly offensive to oust pro-Russian rebels in east Ukraine after fighting had stalled efforts by international investigators to kickstart a probe into the downing of Malaysia Airlines flight MH17.

International fallout from the crisis tearing apart the ex-Soviet nation rumbled on as the Group of Seven major developed economies warned Moscow that it could face even tougher sanctions over its backing for the insurgents, despite the EU and U.S. already hitting Russia with the most punitive measures since the Cold War.

A British judge said Thursday that the Russian state has a case to answer in the radioactive poisoning of Alexander Litvinenko as he formally opened a public inquiry into the death of the former spy.

Judge Robert Owen said he would be able to hear secret evidence behind closed doors about the 2006 murder of Litvinenko, who accused President Vladimir Putin from his deathbed of being linked to his killing.

The European Union formally adopted broad economic sanctions against Russia on Thursday, aiming to make it pay a price over the Ukraine crisis in the hope Moscow will reverse course.

They were published in the EU's Official Journal later in the day, meaning that they come into effect on Friday.

Russia has launched fresh war games involving S-300 surface-to-air missiles on its southern flank as Ukraine demanded that Moscow explain separate three-day drills close to the border.

The war games involving S-300 missiles, SU-24 attack aircraft and MiG-31 supersonic interceptor jets are taking place in the southern Astrakhan region and will end on Friday, a spokesman for the Central military district told AFP on Thursday.