* Gas supplies to Poland cut; no word on Bulgaria

* Ukraine accuses Russia of blackmailing Europe

* Germany sends tanks to Ukraine

* Farmers wear body armour to plough fields

WARSAW/SOFIA/KYIV, April 27

Russia halted gas supplies to Poland under the Yamal contract on Wednesday, data from the European Union network of gas transmission operators showed, in a deepening of the rift between the West and Russia over its invasion of Ukraine.

Bulgaria, like Poland a NATO and EU member, said earlier that Russia would also halt supplies of gas to it. There was no word early on Wednesday if Bulgaria's supplies were also cut.

Ukraine accused Russia of blackmailing Europe over energy in an attempt to break its allies, as fighting heads into a third month without Russia capturing a major city.

Staunch Kremlin opponent Poland is among the European countries seeking the toughest sanctions against Russia for invading its neighbour.

Poland's gas supply contract with energy giant Gazprom GAZP.MM is for 10.2 billion cubic meters (bcm) per year, and covers about 50% of national consumption.

Poland's state-owned PGNiG PGN.WA had said supplies from Gazprom via Ukraine and Belarus would be cut at 8 a.m. (0600 GMT) on Wednesday, but Poland said it did not need to draw on reserves and its gas storage was 76% full.

Russian President Vladimir Putin has called on 'unfriendly' countries to pay for gas imports in roubles, a demand only a few buyers have implemented.

'The ultimate goal of Russia's leadership is not just to seize the territory of Ukraine, but to dismember the entire centre and east of Europe and deal a global blow to democracy,' Ukraine's President Volodymyr Zelenskiy said late on Tuesday.

His chief of staff, Andriy Yermak, said Russia was 'beginning the gas blackmail of Europe'.

'Russia is trying to shatter the unity of our allies,' Yermak said.

Bulgaria, which is almost completely reliant on Russian gas imports, said it had fulfilled all its contractual obligations with Gazprom and that the proposed new payment scheme was in breach of the arrangement.

It has held initial talks to import liquefied natural gas through neighbouring Turkey and Greece.

Gazprom said it had not yet suspended supplies to Poland but that Warsaw had to pay for gas in line with its new 'order of payments.' It declined to comment regarding Bulgaria.

The invasion of Ukraine, launched on Feb. 24, has left thousands dead or injured, reduced towns and cities to rubble, and forced more than 5 million people to flee abroad.

Moscow calls its actions a 'special operation' to disarm Ukraine and protect it from fascists.

Ukraine and the West say this is a false pretext for an unprovoked war to seize territory in a move that has sparked fears of wider conflict in Europe unseen since World War Two.

Russia's ambassador to the United States has warned Washington to stop sending arms to Ukraine, saying that large Western deliveries of weapons were inflaming the situation.

More than 40 countries met in Germany on Tuesday to discuss Ukraine's defence.

Mark Milley, chairman of the U.S. Joint Chiefs of Staff, told reporters while flying to Tuesday's meeting that the next few weeks in Ukraine would be 'very, very critical'.

Germany announced on Tuesday its first delivery of heavy weapons to Ukraine, including Gepard tanks equipped with anti-aircraft guns.

Ukrainian pleas for heavy weapons have intensified since Moscow shifted its offensive to the eastern region of Donbas, seen as better suited for tank battles than the areas around the capital Kyiv where much of the earlier fighting took place.

A series of blasts were heard in the early hours of Wednesday in the Russian city Belgorod near the Ukrainian border, regional governor Vyacheslav Gladkov said, and an ammunition depot in the province was on fire.

Gladkov said no civilians had been hurt by the fire which broke out at a facility near Staraya Nelidovka village. Russia this month accused Ukraine of attacking a fuel depot in Belgorod with helicopters and opening fire on several villages in the province.

The Belgorod province borders Ukraine's Luhansk, Sumy and Kharkiv regions, all of which have seen heavy fighting since Russia invaded Ukraine two months ago.

Fighting continued in eastern and southern Ukraine.

Ukrainian farmers in the southern region of Zaporizhzhia which borders the front line are wearing body armour to plough their fields.

Russia's defence ministry said its forces had 'liberated' the entire Kherson region in southern Ukraine and parts of the Zaporizhzhia, Mykolaiv and Kharkiv regions, Interfax news agency reported. If confirmed, that would represent a significant Russian advance.

Ukrainian authorities on Tuesday dismantled a huge Soviet-era monument in the centre of Kyiv meant to symbolise friendship with Russia, according to the city's mayor.

The eight-metre (27-ft) bronze statue depicted a Ukrainian and Russian worker on a plinth, holding aloft together a Soviet order of friendship. The statue was under a giant titanium 'People's Friendship Arch', erected in 1982 to commemorate the 60th anniversary of the Soviet Union.

'We now see what this 'friendship' is - destruction of Ukrainian cities ... killing tens of thousands of peaceful people. I am convinced such a monument has an entirely different meaning now,' Kyiv mayor Vitaly Klitschko said.

U.N. Secretary-General Antonio Guterres told Russia's foreign minister on Tuesday that he was ready to fully mobilise the organisation's resources to save lives and evacuate people from the besieged Ukrainian city of Mariupol.