Russia held open the door Monday to further talks on resolving its standoff with the West and said some of its military drills were ending, signaling a possible easing of the crisis over Ukraine.

The comments came as German Chancellor Olaf Scholz, visiting Kyiv, vowed that Berlin and Western allies would maintain support for Ukraine's security and independence, urging Russia to take up "offers of dialogue".

During a televised meeting with President Vladimir Putin, Russian Foreign Minister Sergei Lavrov said "there is always a chance" to reach an agreement with the West over Ukraine.

He told Putin that initial exchanges with leaders in European capitals and Washington showed enough of an opening for progress on Russia's ambitions to be worth pursuing.

"I would suggest continuing," Lavrov said. "Fine," Putin replied.

Meanwhile, during a press conference in Kyiv with Ukrainian President Volodymyr Zelensky, Scholz told reporters there was "no reasonable justification" for Russia's build-up of troops around Ukraine's borders.

He also urged Moscow "to take up the existing offers of dialogue".

Ahead of the talks, Ukraine demanded an urgent meeting with Russia to explain why it has deployed more than 100,000 soldiers around its borders.

Over recent weeks, European leaders have warned that the build-up is the worst threat to the continent's security since the Cold War, with Putin demanding a rollback of Western influence in eastern Europe and a ban on Ukraine joining NATO.

'Digging trenches'

Western allies have prepared what they warn would be a crippling package of economic sanctions in response to any attack, the threat of which a German government source said was, "very critical, very dangerous."

Alarm has been fueled by recent Russian military exercises, including with Belarus, where the US said Moscow had dispatched 30,000 troops for more than a week of drills.

Russia's Defence Minister Sergei Shoigu told Putin that some of the drills taking place in Russia and waters around the country were "ending" and more would end "in the near future".

In Kyiv, Ukraine's Defense Minister Oleksiy Reznikov meanwhile hailed "positive" talks with his Belarusian counterpart. He said he had been assured "there are no threats to Ukraine from Belarus".

US intelligence officials worry that weeks of crisis talks have given Russia the time to prepare a major offensive should Putin decide to attack Ukraine.

On Sunday, Washington warned that Russia was ready to strike at "any moment".

Ukraine requested a formal meeting with Moscow earlier Monday and other members of the pan-European security body, the OSCE, that might explain "the reinforcement and movement of Russian forces along our border".

Near the frontline separating Kyiv-held territory from areas under the control of Moscow-backed insurgents in the separatist east, underprivileged children in the care of church groups were helping with war preparations.

"We are digging trenches that Ukrainian soldiers could quickly jump into and defend in case the Russians attack," 15-year-old Mykhailo Anopa told AFP.

Tough trip

Germany plays a central role in efforts to mediate in eastern Ukraine, where a grueling conflict with Russian-backed separatists has claimed more than 14,000 lives.

But Germany's close business relations with Moscow and heavy reliance on Russian natural gas imports have been a source of lingering concern for Kyiv's pro-Western leaders and US President Joe Biden's team.

Scholz has hedged against unequivocally backing Biden's pledge to "bring an end" to Russia's new Nord Stream 2 gas link to Germany -- a project that Zelensky described Monday as "a geopolitical weapon."

Zelensky repeated during the press conference Monday with Scholz that joining the NATO alliance would guarantee Ukraine's survival.

But Ukraine's membership is a sticking point in talks between Russia and the West, which has spurned a demand from Moscow that Kyiv never be admitted from the US-led military bloc.

"We understand that NATO membership would ensure our security and our territorial integrity," Zelensky said.

Scholz will visit Moscow on Tuesday after tit-for-tat closures of the German-language service of Russia's RT network and the Moscow bureau of Germany's Deutsche Welle.

Airline worries

A growing number of Western countries are withdrawing staff from their Kyiv embassies and urging their citizens to leave Ukraine immediately.

But departures may be complicated by the looming threat of the skies over Ukraine closing due to rising risks for airlines.

Dutch carrier KLM became the first major airline over the weekend to suspend flights to Kyiv indefinitely.

On Monday morning, ahead of the potential shutdown, Kiev's international airport was busy but there were no signs of panic despite long queues to depart.

Ukraine's budget airline SkyUp said European leasing companies were demanding that Ukrainian carriers return their planes to EU airspace within 48 hours.

Industry analysts believe other international airlines may soon also ban flights into Ukraine because of the growing cost to insurers.