Russia has moved more troops closer to Ukraine's borders in recent days despite assurances it will not invade, U.S. Defense Secretary Chuck Hagel said Wednesday.

Although Russia's defense minister Sergei Shoigu had told Hagel last week that Moscow would not send troops into eastern Ukraine, "the reality is that they continue to build up their forces," Hagel said.

Romanian President Traian Basescu on Wednesday warned the former communist state could become a target for spies in the wake of Moscow's annexation of Crimea.

"We must definitely take into account the risks of growing espionage activities on Romania's territory in the wake of developments in the region," Basescu said.

Switzerland on Wednesday decided not to impose sanctions against Russia for its seizure of Crimea, claiming it wanted to find a "balance" between international law and Swiss interests.

"The position of our country is independent of the U.N.," Swiss president Didier Burkhalter told a press conference in Bern, saying Switzerland can only use sanctions when they are based upon "international law and the interests of the Swiss".

Germany said Wednesday that Ukraine's former Prime Minister Yulia Tymoshenko had crossed a line with leaked comments in which she is heard urging the "wiping out" of Russians.

Chancellor Angela Merkel's spokesman Steffen Seibert said Ukraine's political leadership must reject "violent fantasies" and strive for stability and inclusion of minorities

Ukraine's leader sought parliamentary approval on Wednesday for military exercises with NATO partners that would put U.S. troops in direct proximity to Russian forces in the annexed Crimea peninsula.

Acting President Oleksandr Turchynov's request came as the chief of Russia's general staff announced in Moscow that his forces were now in full control of all of Ukraine's 193 military bases in the Black Sea region before its seizure by Kremlin forces at the start of the month.

The Russian economy could shrink by up to 1.8 percent this year because of the effects of the crisis in Ukraine, the World Bank estimated on Wednesday.

The World Bank said that if the impact of the crisis turned out to be low because it was resolved in "a peaceful fashion", the economy could grow by 1.1 percent this year.

The Russian flag is now flying over all the military facilities in Crimea, following Moscow's seizure of the region from Ukraine, Russia's top general said on Wednesday.

The announcement by military chief of staff General Valery Gerasimov came after Russian troops on Tuesday stormed the last naval vessel still flying the Ukrainian flag in Crimea and said they now have complete control over all military bases.

Russian security forces on Tuesday killed five suspected Islamist militants in a special operation in Dagestan that also left one serviceman dead, the National Anti-Terror Committee (NAK) said.

"As a result of the clash five criminals were neutralized," it said in a statement quoted by Russian news agencies, naming one as a senior local militant named Tural Atayev, a citizen of Azerbaijan.

Russian troops on Tuesday stormed the last naval vessel still flying the Ukrainian flag on the Black Sea peninsula of Crimea, a regional Ukrainian defense official said.

The raid on the Cherkasy trawler occurred one day after Russian forces took control of the Kostyantyn Olshanskiy, which, like the Cherkasy, had been blocked by Russian ships in western Crimea's Donuzlav Lake, defense ministry spokesman Vladyslav Seleznyov said in a statement published on his Facebook account.

Moldova's pro-Moscow breakaway region of Transdniestr said on Tuesday it had shot down a drone that it said appeared to have come from Ukraine to conduct a reconnaissance mission.

"As a result of measures undertaken by the Transdniestr side the drone has ceased to function," the security service said in a statement.