Kiev urged separatist rebels in war-torn eastern Ukraine on Monday to allow civilians to flee besieged cities in the face of a looming humanitarian crisis, with major power and water shortages.
The call came as Malaysian experts were due to visit the site of downed flight MH17, joining Australian and Dutch police who have been combing the area for remains of the crash victims.
Civilians in the blighted industrial region have borne the brunt of the relentless fighting between government and pro-Moscow rebel forces, with both sides accused of firing on built-up areas, resulting in more than 10 civilian deaths at the weekend.
Ukraine's military called on insurgents in the main rebel-held hubs of Donetsk, Lugansk and another frontline city of Gorlivka to agree to “humanitarian corridors” for several hours each day to allow civilians to escape.
“Civilians can identify themselves with a white flag for groups of people and a wide white armband on the sleeve of each person,” it said in a statement.
The Lugansk mayor has warned that the city of 420 000 was on the brink of a “humanitarian catastrophe” after days without power or running water.
In the main city of Donetsk, where six civilians were killed at the weekend, local authorities reported explosions and bursts of heavy fire throughout the night.
Over 100 000 people have fled for other parts of Ukraine since the fighting erupted in April, according to the United Nations, while Russia claims another half a million have crossed its border in search of refuge.
The exodus continued on Monday with terrified local residents waiting at Donetsk train station surrounded by piles of baggage.
“We are leaving because war is going on. They are shooting. There was shooting half an hour before we left,” Igor, who was heading to the western city of Lviv, told AFP.
“We are not going away forever we are going to friends, to the part of Ukraine where they are not shooting... Terrible things are happening,” his mother Nelya said.
Government forces have made major gains over the past month and say they are close to cutting off fighters in Donetsk from the Russian border and their comrades in Lugansk.
On Monday however, the Ukrainian military said a number of troops were forced to retreat into Russia after hours of missile and mortar bombardment from across the border.
Russia's security services told local media that border guards allowed 438 Ukrainian soldiers to cross into their territory after they agreed to hand over their arms.
Ukraine's Defence Minister Valeriy Geletey had pledged in a BBC interview on Sunday that there “will be victory and very soon” after more than three months of civil war that have claimed over 1 150 lives.
He admitted however that “it would not be easy to liberate” Donetsk and Lugansk where rebels have holed up and pledged to fight to the death.
As the violence continued, Malaysian experts were expected to join the teams combing the vast crash site of the Malaysia Airlines flight that was blown out of the sky on July 17, killing all 298 people onboard.
But Ukraine's government said rebels were blocking access for the 100-strong mission attempting to use sniffer dogs and refrigerated ambulance vans to search for remains strewn across about 20 square kilometres.
So far, about 220 bodies have been flown back the Netherlands - which suffered the most casualties in the crash - for the painstaking identification process.
Another plane carrying remains found over the past few days was set to fly to the Netherlands on Monday.
The United States accuses insurgents of downing MH17 with a surface-to-air missile likely supplied by Russia, while Moscow and the rebels blame the Ukrainian military.
The United States and European Union have slapped Moscow with the toughest sanctions since the collapse of the Soviet Union over the Kremlin's alleged arming and instigation of the separatist rebellion.
In a sign that the sanctions were having an impact, Russian low-cost carrier Dobrolet was forced to cancel all flights from Monday because of scrapped leasing deals for Boeing aircraft.
Germany also said it had cancelled a major deal to provide a fully-equipped training camp to Russian forces.
The measures have yet to quell the fighting however and the United States has warned that Russian support for the rebels is increasing.
Russia on Monday announced new military drills that will involve 100 aircraft on its southern flank in the latest in a series of manoeuvres likely to alarm Ukraine. - Sapa-AFP