Russia's foreign minister vowed to "stop" unrest in eastern Ukraine on Monday, fuelling concerns about escalation of the conflict between pro-Kiev and secessionist forces.

Speaking in Moscow before US vice-president Joe Biden arrived in Kiev for an official visit, Sergei Lavrov warned about a possible Russian military intervention in Ukraine, saying his country faced growing demands to "rescue" its western neighbour.  

"There are more and more calls to Russia for rescue from this lawlessness," Mr Lavrov said.  "That puts us in an extremely complicated situation.  Those who are deliberately trying to trigger a civil war, obviously hoping to provoke a big, serious, bloody conflict, are engaged in a criminal policy.  And we will not only condemn but also stop it."

Mr Lavrov's remarks came a day after a shootout at a roadblock in Slavyansk, a hardcore secessionist stronghold in eastern Ukraine, which killed at least three people and raised doubts over an agreement reached by the US, Russia, Ukraine, the EU and the UN in Geneva last week to de-escalate the crisis.

David Fuller's view

Russia’s move to retake some of the former Soviet Union’s territory is a bad dream coming true for the USA and Western Europe, not to mention East European countries which were quick to establish links with the West when they were no longer ruled by Moscow. 

In stock market terms, an insecure but opportunistic Putin has embarked on an aggressive takeover binge for power, profit and influence.  The USA and Europe are reluctant regulators who need to increase sanctions to avoid bigger problems in future years.