Russia would pay a high price for any new military aggression against Ukraine, NATO and the United States warned on Tuesday as the Western military alliance met to discuss Moscow's intentions for massing troops on the border of the former Soviet republic.

The West has already shown that it can wield economic, financial and political sanctions against Moscow, NATO Secretary-General Jens Stoltenberg told reporters ahead of talks of the alliance's foreign ministers in the Latvian capital Riga.

"There will be a high price to pay for Russia if they once again use force against the independence of the nation, Ukraine," Stoltenberg said.

U.S. Secretary of State Antony Blinken is expected to brief his 29 NATO counterparts on Washington's intelligence on what is going on at the alliance's eastern flank and in Ukraine, which is not a member.

"Any escalatory actions by Russia would be a great concern to the United States... and any renewed aggression would trigger serious consequences," he said at a news conference before the meeting.

"We will be consulting closely with NATO allies and partners in the days ahead... about whether there are other steps that we should take as an alliance to strengthen our defences, strengthen our resilience, strengthen our capacity."

Kyiv's aspirations for integration with the West have triggered a standoff with Moscow.

'MALIGN ACTIVITY'

The Kremlin annexed the Black Sea peninsula of Crimea from Ukraine in 2014 and then backed rebels fighting government troops in the east of the country. That conflict has killed 14,000 people, according to Kyiv, and is still simmering.

Two Russian troop build-ups this year on Ukraine's borders have alarmed the West. In May, Russian troops there numbered 100,000, the largest since its takeover of Crimea, Western officials say.

Moscow has dismissed as inflammatory Ukraine's suggestions that it is preparing for an attack, said it does not threaten anyone and defended its right to deploy troops on its own territory as it wishes.

Britain and Germany echoed the NATO warnings.

"We will stand with our fellow democracies against Russia's malign activity," said British Foreign Secretary Liz Truss.

German Foreign Minister Heiko Maas said: "NATO's support for Ukraine is unbroken... Russia would have to pay a high price for any sort of aggression."

Adding to Western concerns, Belarus on Monday announced joint military drills with Russia on its border with Ukraine. While also a former Soviet republic, Minsk is an ally of Moscow.

Belarusian President Alexander Lukashenko, whom the West accuses of seeking to divide the European Union by sending Middle Eastern migrants to the border of NATO members Poland, Latvia and Lithuania, warned Minsk would not sit on the sidelines in case of war.

"It is clear whose side Belarus will be on," he said, referring to Moscow, whose financial and political backing helped him weather mass public protests in August 2020.