In parts of east Ukraine, a daily struggle to survive

Clutching empty plastic bottles, hundreds of people stand waiting for water in this besieged city, with the almost constant thud of artillery shells echoing in the distance.

More than two months after pro-Russian separatists rose up in east Ukraine, electricity and water have been cut off in this depressed industrial city, food is running low and half the population has fled.

Many of those who remain are getting desperate and local officials, echoed by Russia, warn that a humanitarian disaster is looming in east Ukraine as fighting intensifies between the rebels and government forces trying to prise them out.

"I never thought it would come to this," said Lidia, a woman of 58, standing in line near outside a water treatment plant in Slaviansk, a strategic stronghold held by the rebels.

"I have a daughter, a granddaughter, a mother who is 92 and cannot move and I have to come here and fetch at least 40 litres of water every day. And that's if we don't bathe. Only for drinking and washing clothes for the kid and linen for my mother," she said.

Talk in the queue is of politics and war, with some debating when their nightmare will end. The queuing has become a daily chore since water ran out more than two weeks ago.

The lack of electricity has even caused Slaviansk's morgues to close as they cannot keep bodies cold. Local authorities say undertakers are digging graves under fire.

Many people have had enough and decided to leave. Pensioner Viktor Parhobin is among them, facing upheaval again 20 years after he moved to Slaviansk, a city of 130,000, to escape a war in Russia's Chechnya region.

"Life was good here. Now I have to flee and I have no clue where to go," he said, squatting on the side of the road with his infant granddaughter in his arms as they waited for a bus to take them away to safety.

"Initially we'll resettle in Stavropol in southern Russia, but where we'll go from there I don't know ... all our lives are now in three duffel bags," he said, pointing to a small pile of cheap luggage around him.

The uprising by the separatists, who oppose central rule by Kiev and seek union with Russia, began in April, the month after Russia annexed the Black Sea peninsula of Crimea from Ukraine.

The pro-Western authorities in Kiev accuse Russia of orchestrating the uprising in the east after the ouster of a president sympathetic to Moscow in February. The Kremlin denies it is behind the revolt.

New Ukrainian President Petro Poroshenko has been working on a peace plan but has also intensified a military campaign to prise out the rebels since he was elected on May 25.

The rebels show no sign of surrendering but the fighting has taken its toll on them and on civilians, further alienating east Ukrainians and deepening the nation's divide.

The United Nations said this week 257 civilians had been killed since mid-April. The true toll is likely to be higher as many places have not been accessible to international monitors.

"Kiev has shown it doesn't care about anyone here. Every day more and more people are signing up and we'll stand to the end," a rebel, who gave only his "nom de guerre" of Snake, said as he guarded a bank in east Ukraine's main city, Donetsk.

"We know the Ukrainians are coming and we're polishing our weapons in readiness."

Estimates differ widely on the number of people displaced. The United Nations put it at 17,000 but Russia's Itar-Tass news agency quoted a Russian official as saying on Thursday the number of Ukrainians living just across the border in Russia had swelled by 70,000 to 400,000 in just four days.

Among those that remain, roughly a quarter of the Donetsk region's 4.5 million population are suffering shortages of some or all basic supplies, an official of the self-proclaimed Donetsk People's Republic (DPR) said.

"The biggest issue that we are unable to resolve on our own is the lack of supplies - medical ones in particular," Roman Lyagin, the DPR's labour and welfare minister, said in his office in the sandbagged administration building in Donetsk.

In a nearby building, volunteers sort through piles of clothes, diapers and linen brought to a makeshift aid centre by local rebel supporters. The base also doles out cash and medicine to those in need, though it is running low on both.

Some living in the region are unaffected, but those living in areas where fighting has raged are struggling more and more.

"We haven't received our pensions since April and we need to eat and pay bills and buy medicine. We have nothing to eat now... We called the bank in Kiev to ask how we can get our pension and they told us that on their map Slaviansk does not exist," said a pensioner who gave his name only as Vladimir.

Ukraine stopped electronic payments such as pensions to banks in Slaviansk and neighbouring Kramatorsk because of fears the rebels would steal the money, but officials say residents can still collect state funds at banks in other towns.

But with fuel running short and Ukrainian and rebel roadblocks controlling access to Slaviansk, travelling is difficult for the city's remaining 60,000 residents.

The lack of fuel poses a problem for Slaviansk's ambulance service, which operates three teams instead of the usual eight.

"We're working flat-out, sometimes 48 hours straight regardless of the shelling - you can never tell when it will start and stop," paramedic Zhenya said.

As if to underline his point, a mortar bomb exploded a few hundred metres away, sending a plume of smoke into the air.

The DPR's Lyagin said a significant amount of medical assistance and food has been provided locally or by Russia, which says Kiev and the West ignore the humanitarian crisis.

International efforts have been hampered by security concerns, while the Ukrainian government has not issued formal instructions on the registration and provision of aid to internally displaced persons, the U.N. Human Rights Monitoring Mission in Ukraine said.

There is no direct state aid initiative at the moment, but the government operates a hotline that puts callers in touch with a non-govermental fund supported by private donations.

While many have left to stay with relatives elsewhere in Ukraine or in Russia, others have been put up in state sanatoriums including several in Svyatogorsk, near Slaviansk.

In the small town of Amvrosiivka, near the border with Russia, residents were woken one recent day by shelling that destroyed 23 homes and two shops. No fatalities were reported, but residents face rebuilding their homes on their own.

"We've been able to find a total of 150,000 hryvnia ($12,650) from the town budget for repairs, but it won't go far," Amvrosiivka regional lawmaker Oleksandr Shulga said. "We're not even sure which side is responsible for the attack."

In Luhansk region, residents crossed Ukrainian army checkpoints with only what they could carry. They were abandoning a town called Schastye, which translates as Happiness.

(Writign by Alessandra Prentice; Editing by Timothy Heritage and Peter Graff)