The European Union and the United States have urged Moscow and Kiev to defuse continuing tension over an alleged deadly clash in Crimea, as Germany's foreign minister prepared to travel to Russia for talks on the issue.
Frank-Walter Steinmeier is due to meet Russian counterpart Sergei Lavrov in the Urals city of Yekaterinburg on Monday, to discuss the failing peace process in Ukraine and the conflict in Syria, where Moscow is the main supporter of government forces.
Russia accused Ukraine last week of sending a sabotage unit into Crimea – which the Kremlin annexed in 2014 – and killing two of its servicemen.
Kiev denied the claim, but Russian president Vladimir Putin said his country would respond to the act of "terror" and that there was now no point holding further talks on the crisis with the leaders of Ukraine, Germany and France.
Russian officials also said they might cut diplomatic ties with Kiev, and announced the deployment of a new air defence system to Crimea. Both Ukraine and Russia started war games close to the region, meanwhile.
"The latest escalation in Crimea must be a cause of concern to us. In what is already a difficult situation, no one stands to benefit from further escalation," Mr Steinmeier told German newspaper Welt am Sonntag ahead of his trip to Russia.
“We expect all sides to refrain from taking any steps that could lead to the situation escalating further . . . We are in contact with both Ukraine and Russia on this matter. I will of course also discuss this topic . . . in Yekaterinburg.”
June and July saw a sharp increase in fighting and casualties in eastern Ukraine, where Russia continues to back separatist forces in a conflict that has killed 10,000 people and displaced some two million since spring 2014.
“For weeks now we have been working on a framework agreement aimed at easing tensions,” Mr Steinmeier said.
“It has not been possible to reach agreement so far, as neither side is willing to compromise . . . there has been no tangible progress either as regards improving the security situation in eastern Ukraine or reaching the necessary consensus on local elections.”
The US vice-president Joe Biden and EU foreign affairs chief Federica Mogherini spoke to top Ukrainian officials in recent days and urged Kiev and Moscow to calm the situation.
The Pentagon, meanwhile, said it did not see an imminent threat to Ukraine in Russia’s latest troop manoeuvres.
