US Vice President Joe Biden yesterday called on European allies to stand firm in punishing Russia for its role in the unrest in neighbouring Ukraine and its annexation of Crimea.
Embarking on a visit to reassure Eastern European nations of America's support for the region, Biden said they all "must remain resolute in imposing greater costs on Russia and imposing those costs together".
"Europe's borders should never again be changed at the point of a gun, which is why we continue to condemn - condemn - Russia's illegal occupation of Crimea," Biden said as he met American and Romanian forces involved in joint military exercises.
The US and the European Union have imposed travel bans and asset freezes on President Vladimir Putin's inner circle over Russia's annexation of the Crimea Peninsula and threatened to target entire sectors of the Russian economy with sanctions if Russia tries to grab more land or attempts to derail Ukraine's presidential election.
"But our strategy is about more than just imposing costs. It's fundamentally about investing in a revitalised Nato that emerges from this crisis and works toward a successful summit in Wales stronger and more united," Biden said.
Since Crimea was annexed, Nato has put surveillance planes in the skies over Poland and Romania, dispatched warships to the Baltic and Black seas and sent US Army troops to Poland, Romania and the Baltic states.
Russian Prime Minister Dmitry Medvedev hit out at the sanctions, saying Russia was being pulled into a new cold war with the US and its allies, who are were using economic warfare reminiscent of the Soviet Union under Leonid Brezhnev.
Russia had prepared a raft of retaliatory steps in response to potentially wider sanctions imposed by the US and the European Union, Medvedev said on Monday in an interview with Bloomberg Television.
While he didn't give details of Russia's potential steps, he described the punitive measures as a double-edged sword.
"We are slowly but surely moving towards a second cold war, which no one needs," Medvedev said. He blamed US President Barack Obama for a lack of "political tact".
Additional reporting by Bloomberg