SOCHI, Russia - Russia's president may sever diplomatic ties with Ukraine if there are no other options available, Russian Prime Minister Dmitry Medvedev said Friday amid the recent escalating tensions between Moscow and Kiev.

"I would not want that to happen, but if there is no other option left to impact the situation, the president could make such a decision," he was quoted by the Interfax news agency as saying.

Tensions between Russia and Ukraine have been escalating as Russian President Vladimir Putin on Wednesday accused Kiev of plotting terrorist attacks in Crimea and vowed to take additional measures to ensure the safety of the infrastructure and citizens there.

The Russian Federal Security Bureau said Wednesday the country had prevented a series of terrorist attacks in Crimea orchestrated by the Ukraine military intelligence service, in which two Russian servicemen were killed.

However, Ukrainian President Petro Poroshenko denied Russia's accusations, calling them "preposterous and cynical."

Medvedev called the incident "a crime against the Russian state and the Russian people, who live in one of the territories of the Russian Federation."

Crimea, which was previously part of Ukraine, was incorporated into Russia in 2014 following a referendum, which was recognized by Moscow but rejected by Ukraine and Western powers.

Putin relieved Mikhail Zurabov of his duties as Russian ambassador in Kiev on July 28. His successor has not been appointed so far.