The US urged Russia on Wednesday to pull back its troops from the Ukrainian border, warning that a Russian invasion would provoke sanctions that would hit Moscow harder than any imposed until now.

“We don’t know whether President (Vladimir) Putin has made the decision to invade. We do know that he is putting in place the capacity to do so in on short order should he so decide,” US Secretary of State Antony Blinken said.

“Should Russia follow the path of confrontation, when it comes to Ukraine, we’ve made clear that we will respond resolutely, including with a range of high impact economic measures that we have refrained from pursuing in the past,” he said.

Blinken was speaking in the Latvian capital Riga after conferring with foreign ministers from Nato and Ukraine on how to respond to what Kyiv says is a Russian build-up of more than 90,000 troops near its border.

Russia seized the Crimean peninsula from Ukraine in 2014 but denies aggressive intent in the current crisis and says it is responding to threatening behaviour by Nato and Ukraine.

The Kremlin said it feared Ukraine was gearing up to try to recapture by force areas controlled by pro-Russian separatists in the Donbass region in the east of the country — something Kyiv denies — and accused it of “very dangerous adventurism.”

It said Russia could not take any steps to de-escalate because of a large concentration of Ukrainian forces close to the border. Ukrainian foreign minister Dmytro Kuleba said Europe faced a critical moment and Russia was trying to shift the blame onto Ukraine. “I would like again to officially state that Ukraine does not plan any military offensive in Donbass.”