A unilateral ceasefire called by Vladimir Putin appears to have had little effect on the ground, with Ukrainian officials accusing Russians of opening fire in several areas.

A Ukrainian rescue worker was killed in a Russian strike, while Russian state TV said the city of Donetsk was hit.

Russia ordered a 36-hour unilateral ceasefire, to coincide with the Orthodox Christmas.

Ukraine rejected it saying Moscow might use it to reinforce troops.

Russia's defence ministry insisted it was observing the truce along the entire "line of contact", starting at 12:00 Moscow time (09:00 GMT) on Friday.

It said its forces had only returned fired during the ceasefire when the Ukrainian army had attacked Russian positions.

Air alerts were reported across Ukraine shortly after the purported truce began, and then the governor of Kherson region said a strike on a fire station had left one rescuer dead and four other people wounded in the main city, which was liberated in November by Ukrainian forces.

The eastern city of Kramatorsk also came under attack and more than a dozen buildings were damaged, Ukrainian officials said.

Luhansk regional leader Serhiy Haidai warned that Russia's Christmas truce was "a lie and a trap", advising residents not to attend Orthodox Church services or gather in crowded places as the Russians could plan "terrorist attacks".

Kyiv Mayor Vitaliy Klitschko warned that overnight temperatures in the capital would drop to -11C and called for electricity to be carefully used.

Ukraine's President Volodymyr Zelensky said the truce was an attempt to stop his country's military advances in the east of the country, and bring in more men and equipment.

Artillery fire could be heard on both sides of the front line in the eastern city of Bakhmut, where Russian forces have concentrated much of their firepower in an attempt to push west towards Kramatorsk.

Russia's Wagner mercenary group leader, Yevgeny Prigozhin, said this week that Ukrainians had turned every house in the city into a fortress. Satellite images released on Friday revealed the effects of the battle since last August.

Although Russian officials insisted the truce remained intact, there was no indication of any significant lull in fighting.

"We are two and a half hours into this proclaimed ceasefire, and actually the whole territory of Ukraine is under air raid alert. So I think that speaks for itself," Ukrainian MP Inna Sovsun told the BBC. "Basically the ceasefire, the Russians are making it up."

The Russian Orthodox Church - the largest of the Eastern Orthodox Churches - celebrates Christmas Day on 7 January, according to the Julian calendar.

Some people in Ukraine celebrate Christmas on 25 December, others on 7 January. Both days are public holidays in the country.

This year, for the first time, the Orthodox Church of Ukraine said it would allow its congregations to celebrate Christmas on 25 December, as do some other denominations in western Ukraine.

(editor-in-charge：Press center8)