Russia has threatened to switch to other trade partners if the European Union and the United States impose economic sanctions against Moscow.

In an interview to BBC, President Vladimir Putin's spokesman Dmitry Peskov said, if an economic partner in one part of the world decides to slap sanctions on Russia, Moscow will shift its attention to other partners in other parts of the world.

He further said, Russia wants to stay on good terms with the EU and US, especially with the EU, because the European Union is Russia's key economic, investment and trade partner. He said, Russia is not going to start military operations in eastern regions of Ukraine.

As for the death of a Ukrainian serviceman in Crimea yesterday, he said the pro-Russian Crimean forces are facing provocations from those wishing to cause conflict.

Russia had earlier told the United States that Western sanctions over the Crimea dispute are unacceptable, and has threatened consequences.

Russian Foreign Minister Sergei Lavrov issued the warning in a telephone call to his American counterpart John Kerry.

It came hours after Russian and Crimean leaders signed a treaty absorbing the Black Sea peninsula into the Russian Federation.