KIEV, Aug. 16 – Russia, by recently building up tensions with Ukraine, is seeking to put pressure on Western powers to remove painful economic sanctions imposed two years ago, the head of a Russian think tank said Tuesday.

"It's about sanctions," Andrey Kortunov, director general of the Russian International Affairs Council, a Moscow-based foreign policy think tank close to the Russian Foreign Ministry, told Reuters.

"It looks like a way of increasing pressure on Western participants of the Minsk peace process," he said of a peace deal set up for eastern Ukraine, where pro-Russian separatists have battled against government forces.

For two years, Russia has been under U.S. and EU sanctions over its annexation of Crimea and support for the separatists in eastern Ukraine. European leaders say the sanctions cannot be lifted unless the Minsk peace deal is implemented, but for now it looks moribund, with fighting occasionally flaring and both sides blaming each other for failing to implement truce terms.

This week, tension escalated dramatically after Putin threatened to take unspecified counter-measures against Ukraine to retaliate for what his spies say was a plot to bomb targets across contested Crimea. Putin said two Russian servicemen were killed in a clash with Ukrainian saboteurs sent to Crimea.

Kiev says the incident never happened, and was concocted to create a phoney pretext for a new invasion. The United States and European Union also say there is no evidence it took place.

Whether the plot is real or imagined, Moscow has cranked up its military activity in Crimea at the same time as holding a series of what it says are pre-planned war games and missile deployments in the area.

Putin, who is expected to visit Crimea later this week in a show of support, convened his Security Council and canceled the next round of international talks meant to turn the shaky ceasefire in eastern Ukraine into a lasting peace.

But his response - deliberately refocusing international attention back on eastern Ukraine and the lack of progress in implementing a peace deal there - suggests Putin is trying to milk the latest Crimean crisis as part of a diplomatic power play he hopes will eventually kill Western sanctions.

European talks between Russia, Ukraine, France and Germany meant to ensure the peace deal's implementation have so far run into the sand. And talks between Victoria Nuland, U.S. assistant secretary of state, and Vladislav Surkov, a Russian presidential aide, have not generated a breakthrough either.

In the meantime, pro-Kremlin separatists continue to control two self-declared republics in Donbas, eastern Ukraine, where low-level fighting with Ukrainian government forces continues, sometimes flaring up in a big way, despite the ceasefire.

Under the deal, Kiev committed to grant Donbas special status, to pardon separatist fighters, and to organize elections. But in a country ripped apart by more than two years of war that has lost control of giant chunks of territory, following through on such pledges is politically toxic.

Kiev justifies its slowness to act by accusing Russia of failing to meet its own obligations: continuing to stir conflict in the east, and failing to give back control of Ukraine's eastern border.

Kortunov said the aim of Putin's latest saber rattling is to persuade Ukraine's Western allies "to exert influence on Kiev to get it to fulfill its side of the bargain".

Ultimately, Putin wants the world to forgive and forget Russia's Crimean annexation and for the conflict in the east to freeze, leaving a pro-Russian stronghold inside Ukraine, outside of Kiev's control. (rt/ez)