Ukraine and Russia blamed each other for a spike in shellings on the front line in eastern Ukraine that sent Ukrainians fleeing to cellars and other shelters, while some civilians were evacuated.
Pro-Russian separatists have accused Ukraine of planning an offensive into their enclave, despite Russia’s massive military build-up surrounding Ukraine's borders.
Kyiv and Western capitals ridicule this idea and accuse Moscow of attempting to provoke Ukraine and plotting to fabricate incidents to provide a pretext for Russian intervention.
Kinzhal and Tsirkon
President Vladimir Putin oversaw a dramatic military exercise involving nuclear-capable missiles Saturday as tensions over Ukraine continued to mount.
Russian television showed images of Putin and Belarusian leader Alexander Lukashenko seated at a round table in the Kremlin situation room, in front of a bank of screens showing military commanders as they test-fired their latest hypersonic, cruise and nuclear-capable ballistic missiles.
Russian military exercises in Belarus will continue past their scheduled end date, Minsk announced Sunday, leaving Moscow with a large force near the northern Ukraine border.
Moscow had previously said the 30,000 troops it has in Belarus were simply carrying out readiness drills with its ally, which would be finished by Feb. 20, allowing the Russians to head back to their bases.
But, as the day arrived for the operation to end, the Belarus defense ministry said Putin and Lukashenko had decided to "continue inspections," citing increased military activity on their shared borders and an alleged "escalation" in eastern Ukraine.
Russian President Vladimir Putin and his U.S. counterpart Joe Biden have agreed to a summit — to be held only if Moscow does not invade Ukraine, France announced Monday following a frantic new round of diplomacy to avert an all-out war.
Both leaders have said yes in principle to the summit, proposed by French President Emmanuel Macron, his office said, with the White House confirming Biden's willingness, though it was notably cautious.
The U.S. Embassy in Moscow warned Americans late Sunday of potential attacks in public places in Russia, including in Moscow and St. Petersburg, "as well as in areas of heightened tension along the Russian border with Ukraine."
Citing unspecified media sources, the Embassy said the attacks could target “shopping centers, railway and metro stations, and other public gathering places in major urban areas." It told Americans in Russia to "avoid crowds" and "have evacuation plans that do not rely on U.S. government assistance."
Russian Foreign Ministry spokeswoman Maria Zakharova criticized the alert on social media, asking "What are we to make of this?" and questioning whether the American side had followed protocol by making the announcement before sharing its information with Russia.
At least six anti-war activists picketing against the feared Russian invasion of Ukraine were detained in central Moscow on Saturday.
Three of them were kept in custody overnight on protest-related charges, according to the police-monitoring website OVD-Info.
AFP contributed reporting.