(NewsNation) — As the war in Ukraine drags on, opposition to Russia has grown stronger in Europe. And after a commitment from NATO allies to continue arming Ukraine throughout the conflict, Russia is hitting back, using Europe’s reliance on Russian energy to do so.

Russia’s state-controlled natural gas giant Gazprom said it is cutting cut gas supplies to Poland and Bulgaria after they have refused to pay for the shipments in rubles.

It warned that if they siphon gas intended for other European customers, the deliveries to Europe will be reduced to that amount.

The move follows Russian President Vladimir Putin’s order to switch to rubles in payments for the Russian gas supplied to Europe.

“This is, of course, a turning point,” said Polish Strategic Energy Infrastructure Minister Piotr Naimski. “The Russians are spending it up, but we can handle it.”

For now, Bulgarian and Polish leaders say the summer months ahead will help lower demand.

However, European Commission President Ursula von der Leyen said Gazprom’s announcement was another attempt by Russia to use gas as an instrument of blackmail. 

However, Kremlin spokesman Dmitry Peskov dismissed accusations that Moscow has used natural gas supplies as a tool of blackmail after Russian energy giant Gazprom halted gas exports to Poland and Bulgaria.

He said Russia was a reliable energy supplier and was not engaging in blackmail.

Peskov declined to say how many countries had agreed to switch to paying for gas in rubles in line with a decree issued last month by Putin.

Meanwhile, concern has recently increased over the prospect of the conflict widening in Moldova, where pro-Russian separatists have reported attacks this week in a region occupied since the 1990s by Russian troops.

Explosions rocked the separatist region of Trans-Dniester in neighboring Moldova, knocking out two powerful radio antennas and raising fears the war could spill over Ukraine’s borders. No one claimed responsibility for the attacks — the second in as many days — but Ukraine all but blamed Russia.

It was an alarming sign, according to Ukrainian President Volodymyr Zelenskyy that Russia intends to go beyond Ukraine in its invasion.

“The reason is clear. In order to destabilize the situation in the region, to threaten Moldova by showing that if Moldova supports Ukraine, there will be these steps,” Zelenskyy said.

This happened in the hours after United Nations Secretary General António Guterres met with Putin in Russia, hoping to move further toward peace.

The two leaders announced an agreement in principle that the United Nations and the International Committee of the Red Cross should be involved in evacuating civilians from a besieged steel plant in Ukraine’s southeastern city of Mariupol.

U.N. spokesperson Stephane Dujarric said that during their one-on-one meeting Tuesday, Guterres and Putin “discussed the proposals for humanitarian assistance and evacuation of civilians from conflict zones, namely in relation to the situation in Mariupol.”

However, an aide to the Mariupol Mayor Vadym Boichenko said Russian forces had renewed their attacks on the Azovstal steel plant, where fighters and some civilians are holed up. No agreements had been reached on trying to evacuate civilians from Mariupol on Wednesday.

Russian attacks have almost completely destroyed the steel plant, but it is the last pocket of organized Ukrainian resistance in Mariupol.

An estimated 2,000 troops and 1,000 civilians are said to be holed up in bunkers underneath the wrecked structure.

But even as efforts to protect civilians may be underway, Russian leaders are escalating their rhetoric. Russian Foreign Minister Sergei Lavrov says the possibility of both nuclear war and World War III are realistic scenarios, saying loose talk about nuclear escalation was the “height of irresponsibility.”

Lavrov warned the West on Monday not to underestimate the elevated risks of nuclear conflict over Ukraine and said he viewed NATO as being “in essence” engaged in a proxy war with Russia by supplying Kyiv with weaponry.

The invasion of Ukraine has left thousands dead or injured, reduced towns and cities to rubble, and forced more than 5 million people to flee abroad. Moscow calls it a “special operation” to disarm Ukraine and defeat fascists.

The Associated Press and Reuters contributed to this report.