MOSCOW (NYTIMES, BLOOMBERG) - Thousands of Russian troops on Thursday (Feb 10) began 10 days of exercises in Belarus, and Ukraine warned of upcoming Russian naval drills so extensive that they would block shipping lanes, as the Kremlin continued to tighten its military vise on Ukraine.

In Moscow, Russia's top diplomat, Foreign Minister Sergey Lavrov, gave a bleak assessment of the diplomatic efforts aimed at deterring a full-scale invasion. He dismissed his talks with his British counterpart as a conversation of a "mute person with a deaf person", asserting again that the West was not seriously addressing Russia's most pressing concerns.

President Vladimir Putin was slightly more conciliatory, telling reporters on Thursday that negotiations with the West were continuing over Russia's demands to reshape the security architecture of Eastern Europe.

He said that Russia was preparing written responses in its back-and-forth with the United States and the North Atlantic Treaty Organisation (Nato) alliance, and added that he planned to speak by phone in the coming days with French President Emmanuel Macron.

But the intensifying Russian military activity north, east and south of Ukraine gave an ominous undertone to the diplomatic scramble.

Satellite images collected on Wednesday and Thursday revealed new deployments of Russian military equipment and troops in Crimea, western Russia and Belarus.

The new imagery, released by a Colorado-based space technology company Maxar Technologies, shows new or additional deployments in three locations in Crimea, the Black Sea peninsula that Russia seized from Ukraine in 2014.

Those deployments include troops, vehicles and other equipment in Novoozernoye and Slavne near the western coast, and more than 550 new tents for troops and hundreds of vehicles at a disused airfield in Oktyabrskoe, near the center of the peninsula.

The satellite images also show additional military assets were moved to the Kursk area in western Russia. That puts them near the strategic city of Kharkiv, Ukraine’s second-largest, which has a large Russian-speaking population.

In Belarus, Ukraine's northern neighbour and Russia's closest international ally, Russian fighter jets launched air patrols and Russia's potent S-400 air defence systems were deployed near the Ukrainian border.

Russian marines normally based in eastern Siberia - more than 2,500 miles (4,023km) away - practised urban warfare during the drills, the Russian Defence Ministry said.

And off Ukraine's southeastern coast, in the Black Sea and the Sea of Azov, Russia was preparing to hold large-scale naval exercises - prompting a protest from Ukraine that they would block vital trading routes.

“Unprecedented coverage of manoeuvres does not allow navigation in both seas,” Ukraine's foreign ministry said. “This is a significant and unfounded justification for the activities of international shipping, especially trade, which can cause complex economic and social consequences, especially for the ports of Ukraine.”

Ukraine said the planned drills were "an abuse of international law" by Russia "in order to achieve its own geopolitical goals", and it called on other countries to respond by barring Russian ships from their ports.

Ukraine's seaports of Odessa, Mykolaiv, Kherson, Mariupol and Berdyansk, which could be disrupted by the Russian military exercises, are gateways for the vast grain exports from Ukraine's black earth farming zone, along with coal, steel and other commodities important for the country's economy.

Russia rejected those accusations. Moscow described all the drills as legal under international law and promised that Russian troops would leave Belarus after the exercises there conclude on Feb 20. But Western officials worry that the exercises are a cover to position more Russian forces around Ukraine, giving Mr Putin the ability to launch an invasion on short notice.

Western officials have said they do not believe Mr Putin has made a decision to invade. But combined with Russia's recent buildup on Ukraine's eastern border and in Crimea, the troops in Belarus and the amphibious landing ships and other warships gathering off Ukraine's coast created the sense of a noose tightening around Ukraine.

"This is a dangerous moment for European security," said Mr Jens Stoltenberg, Nato's secretary-general, describing Russia's military deployment to Belarus as its biggest since the end of the Cold War. "The warning time for a possible attack is going down."

The joint news conference in Moscow by the top British and Russian diplomats offered a stark display of the clashing worldviews that have made the crisis over Ukraine appear nearly impossible to resolve.

Foreign Secretary Liz Truss of Britain, making a hastily scheduled visit, reiterated Western warnings that an invasion of Ukraine would result in "a prolonged and drawn-out conflict", and that Russia needed to pull back the 130,000 troops that US and Ukrainian officials estimate it had massed near Ukraine's borders.

Mr Lavrov countered by repeating the Russian government's contention that it was not threatening anyone and, therefore, had no reason to de-escalate.

"You first have to prove to me that we are the ones who created this tense situation," Mr Lavrov said, rejecting the idea of a Russian invasion as bordering on farce. The West "is trying to make a tragedy out of this, while, increasingly, it's similar to a comedy".

While Mr Macron sought to strike a constructive tone after meeting on Monday with Mr Putin for five hours in Moscow, little optimism emerged from Ms Truss' visit.

"I am honestly disappointed that we're having the conversation of a mute person with a deaf person," Mr Lavrov said. "It's as though we are hearing each other but not listening."

Russia has made a series of demands of the West, including scaling back the Nato military presence in Eastern Europe to 1990s levels, and guaranteeing that Ukraine could never join Nato. The US has called those demands "non-starters'' and instead offered a series of proposals aimed at arms control.

Despite the apparent impasse, Western diplomatic efforts are continuing.

In Berlin, Chancellor Olaf Scholz met with the leaders of Estonia, Latvia and Lithuania, which all border on Russia. The three Baltic nations welcomed Germany's recent commitment to send an additional 350 troops to the German-led Nato mission in Lithuania. But they expressed frustration with Berlin's decision not to supply defensive weapons to Ukraine and hinted that as a key Nato ally, Berlin should shore up its military spending.

British Defence Minister Ben Wallace is expected to visit Moscow on Friday to meet his Russian counterpart. And next week, Mr Scholz is due in Moscow for talks with Mr Putin.

General Mark Milley, chairman of the Joint Chiefs of Staff, called his Belarusian counterpart, Major-General Viktor Gulevich, according to Belarus. The two discussed "regional security related issues of concern", the Pentagon said, aiming to "reduce chances of miscalculation".

British Prime Minister Boris Johnson said during a visit to Nato headquarters in Brussels on Thursday that he did not think Russia had made a decision on whether to launch an invasion. "But that doesn't mean it is impossible that something absolutely disastrous could happen very soon indeed," Mr Johnson said.