Russia's Foreign Minister Sergei Lavrov has warned the US not to take 'hasty and reckless steps' in response to the crisis in Ukraine's Crimea region.
In a phone call with his US counterpart John Kerry, Mr Lavrov said imposing sanctions on Moscow would harm the US.
Pro-Russian troops have been in control of Crimea for the last week.
Earlier, a stand-off involving pro-Russian soldiers at a Ukrainian military base outside Sevastopol reportedly ended without incident.
Russia's parliament has promised to support Crimea if it chooses to become part of Russia.
The vote has been denounced as 'illegitimate' by the interim government in Kiev, which took power after President Viktor Yanukovych fled to Russia last month in the wake of mass protests against his government and deadly clashes with security forces.
In their telephone conversation on Friday, Mr Lavrov warned Mr Kerry against taking 'hasty and unthought-through steps capable of causing harm to Russian-US relations', Russia's foreign ministry reports.
Mr Lavrov said imposing sanctions on Russia in response to its involvement in Ukraine 'will inevitably have a boomerang effect against the US itself'.
The US State Department said Mr Kerry had 'underscored the importance of finding a constructive way to resolve the situation diplomatically, which would address the interests of the people of Ukraine, Russia and .