Vladimir Putin placed Russian armed forces on alert yesterday in a show of strength over the political direction of Ukraine that rattled financial markets and brought a stern rebuke from the US.

Mr Putin ordered a surprise drill by forces in western Russia, including areas bordering Ukraine. Sergei Shoigu, defence minister, insisted that the exercise was “unrelated to events in Ukraine”, but John Kerry, US secretary of state, nevertheless made clear that any sign of intervention would not be acceptable to Washington.

He urged Moscow “to be very careful in the judgments that it makes” over Ukraine. “We are not looking for confrontation,” he said. “We are making it clear that every country should respect the territorial integrity here, the sovereignty of Ukraine. Russia has said it would do that and we think it’s important that Russia keeps its word.”