The sun is shining and the waves of the Sea of Azov look warm and inviting. But its sandy beaches are empty -- not surprisingly since they run right through the Ukraine conflict's front line.

The shallow sea bordered by Russia and Ukraine was once a cheap and cheerful bucket-and-spade destination for those not bothered by basic facilities and heavy industry right on the shoreline.

But the armed conflict that broke out in April 2014 has put paid to the area's appeal as a holiday getaway, worsening economic hardships for its inhabitants.

With some half million residents, the seaside city of Mariupol is the largest town in eastern Ukraine still under Kiev's control.

A handful of beaches in the city and in villages to its southwest are still theoretically open to visitors, but are seen as practically on the front line.

Yury, the manager of the Gold Fish Hotel in the village of Melekine, sat in one of the bedrooms waiting for guests that never came.

"Last year, at least some of those fleeing Donetsk came here, to wait out the shelling. But this year, people are scared of the war and a lot of them simply don't have money to go on holiday," the 60-year-old manager said.

Only one hotel named Svitlana is full, but its guests are Ukrainian troops, and its beach has signs warning of mines.

"We used to take holidaymakers out for rides in our motorboat. But this year there are no visitors," said 20-year-old Olexander, who lives in the nearby village of Rybatskoye.

"I had to look for another job to somehow earn my bread. I had to go and fish," he said, bringing in a catch of gobies, a type of small fish.

For those living in separatist territory, going to the Kiev-controlled beaches now involves lengthy crossings through army checkpoints.

For some, it is not worth the hassle.

- Disaster destination -

"It was nearby and it was cheap so we took the kids there every year," said a 50-year-old housewife named Vera, who lives near the separatist hub of Donetsk and used to take her grandchildren to stay at a guesthouse on the coast.

"Now I don't want to take children through the lines at checkpoints only for them to hear explosions... or tread on a tripwire on the beach."

Those who do venture onto the beaches are effectively entering a military zone.
They are warned not to swim up to Ukraine's offshore military installations put in place to protect it from airborne attackers. Some of the defences are mined.

"Holidaymakers have to follow the rules: don't take photos, don't come close, don't swim over to the defences, don't provoke the soldiers," said Yaroslav Chepurnoy, spokesman for the anti-terrorist operation in the area.

The Ukrainian military also warn that the pro-Russian rebels are sending explosive devices floating down from the coastline they control east of Mariupol.

A fisherman has been killed, while another explosion blew up a motorboat, killing both on board, Chepurnoy said.

Just 20 kilometres (12 miles) to the east of Mariupol, the village of Shyrokyne has seen some of the conflict's fiercest fighting. Not a single building there is undamaged by the barrage of shelling, including its guest houses and hotels.

To the east, Russian separatist forces are stationed in several former resorts.

Ukrainian troops joked that the area's only hope is to relaunch as a zone for extreme tourism.

"I don't know what kind of mother would dare to bring her child here, where there's constant shelling," said the deputy commander of the Donbass battalion, nicknamed "Grey-Haired". Behind him, smoke from shelling rose from Shyrokine.

"People could only come here for extreme thrills."