Russia threatens to cut off Moldova's gas, again

"Today is the scheduled date of payment. Yet, there is no payment," Kupriyanov said.

"I confirm that Moldovagaz received such a notification from Gazprom," Vadim Ceban, the CEO of Moldovan gas distributor Moldovagaz, also told Reuters.

"We are actively working with the government to solve the problem by the deadline stipulated in the notification. I hope that we will manage to solve this problem," he added.

The new emergency comes after the two sides negotiated a long-term supply contract last month, narrowly avoiding a national emergency in Moldova, which gets almost all its gas from Russia.

The talks involved Russia telling Moldova it should dilute its ties with the EU if it wanted a deal, according to Moldovan sources, in a quid pro quo denied by Russia at the time.

And Russia's latest show of power on the energy front comes amid Moscow's push to get Germany to let it use its Nord Stream 2 gas pipeline as a monopoly despite EU free-market laws.

But for its part, the US hit back at Russia also on Monday by blacklisting a Russian-linked firm, Transadria, and two ships involved in the pipeline operation.

"We continue to work with Germany and other allies and partners to reduce the risks posed by the pipeline to Ukraine and frontline Nato and EU countries and to push back against harmful Russian activities, including in the energy sphere," US secretary of state Antony Blinken said.

Nord Stream 2 bypasses Poland and Ukraine and would help Russia to cut off both Western allies in the event of a conflict.

Ukrainian military commanders also say it would embolden the Russian military by removing a potential problem for Russia if Ukraine's pipelines, which transit Russian gas to the EU, were damaged in new fighting.

Meanwhile, the Moldova gas scare comes amid rising tension on the Belarus-Poland and Russia-Ukraine borders.

Belarus president Alexander Lukashenko on Monday railed at the EU for not helping him to take care of the thousands of migrants he has flown in from the Middle East and forced to attack Polish border guards.

"We must demand that the Germans take them," he said, referring to a group of 2,000 asylum seekers.

He claimed German chancellor Angela Merkel had promised him that the EU would take in people during phone calls in recent days.

"I'm still waiting for the EU to give us a response about 2,000 refugees ... they haven't even contacted us," Lukashenko said.

But for their part, Germany and Austria showed little sign of making any accommodation.

German foreign minister Heiko Maas, on Monday, denounced Belarus' "cynical misuse of migrants".

"The idea of having a humanitarian corridor to Germany for 2,000 migrants is not a solution that is acceptable to Germany or the EU," an Austrian government spokesman also said.

"The EU must not give in to blackmail from Lukashenko," Austrian chancellor Alexander Schallenberg added.

At the same time, Russia has built up an invasion force on Ukraine's eastern border, with Kyiv saying on Sunday it had intelligence that Moscow was preparing to attack early in the new year.

For their parts, the Italian prime minister Mario Draghi and Russian president Vladimir Putin discussed the situation by phone on Monday.

"Of particular concern are provocative steps by the Ukrainian side to deliberately exacerbate the situation in Donbas, including the use of weapons prohibited by the Minsk package of measures," Putin said, referring to a region in east Ukraine and an old ceasefire deal signed in the Belarusian capital.

He also "confirmed Russia's willingness to provide Europe with failsafe natural gas exports on a long-term basis, including by using the potential of the Nord Stream 2 pipeline", according to the Kremlin readout.