Top level talks between the United States and Russia to try to find agreement over Ukraine have ended in stalemate.
Russian Foreign Minister Sergei Lavrov met US Secretary of State John Kerry in London on Friday, two days before a planned referendum in Crimea on whether to leave Ukraine and join the Russian Federation.
Mr Lavrov said Russia and the US have "no common vision" on the crisis in Ukraine though he called the meeting constructive.
The Russian minister said Moscow would respect the result of Sunday's referendum in Crimea but Mr Kerry said the US would not recognise it, and expressed America's deep concern about Russia sending troops to the Ukraine border and in Crimea.
Russia's military intervention in the Crimean peninsula - part of Russia until 1954 and host to its Black Sea fleet - followed the fall of Ukraine's pro-Moscow President Viktor Yanukovych on 22 February.
Moscow has not recognised the interim government that took over in Kiev following Mr Yanukovych's departure, the BBC reports.
On Thursday Russia announced it would hold artillery drills near its border with Ukraine.
The US and the European Union have said that Sunday's vote in Crimea violates international law and the Ukrainian constitution, and are planning to impose sanctions against Russian officials if the crisis does not ease.