Prime Minister Dmitry Medvedev visited Crimea on Monday, the first Russian leader to travel to the Black Sea region after Moscow seized it from Ukraine.

"Am in Simferopol. Today the government will discuss the development of Crimea," Medvedev wrote on Twitter.

The United States is giving ex-Soviet Moldova $10 million to strengthen security on its border with Ukraine, Washington's top diplomat in Europe Victoria Nuland said Sunday.

Part of Moldova's eastern border with Ukraine is occupied by the breakaway Russian-speaking region of Transdniestr.

U.S. Secretary of State John Kerry meets his Russian counterpart on Sunday hoping to ease global tensions over the Kremlin's annexation of Crimea and sudden buildup of troops near Ukraine.

The latest attempt to resolve the worst East-West standoff in the post-Cold War era follows a sudden call placed by Vladimir Putin on Friday to U.S. President Barack Obama -- the first by the Russian leader since he sent troops into Ukraine's Black Sea peninsula in response to the February 22 fall in Kiev of a pro-Kremlin regime.

Russian President Vladimir Putin wants to carry on the frequent "tough but constructive" contacts he has had with Chancellor Angela Merkel on the Ukraine crisis, his spokesman has told German TV.

Dmitry Peskov told ZDF television that the telephone talks between Putin and Merkel were worth their "weight in gold", according to excerpts released ahead of broadcast on "Berlin Direkt" later Sunday.

Russian Foreign Minister Sergei Lavrov on Sunday called on Western powers to back a proposal for Ukraine's Russian-speaking regions to have greater powers in a "federal" structure.

"If our Western partners are ready, then Russia, the United States and the European Union could form a support group on Ukraine and formulate shared appeals to those now in power in Kiev," Lavrov said in an interview with Russian state television.

As the rest of Europe prepares to set their clocks one hour forward for summer on Sunday, residents of Crimea braced for a two hour jump into the timezone of their new masters in Moscow.

To seal Russia's takeover of the formerly Ukrainian peninsula, a symbolic ceremony will be held to move the clocks forward at the railway station in the main city of Simferopol.

Russia's foreign ministry said Saturday that Moscow and Washington still had significant differences over ways to settle the Ukrainian crisis despite ongoing consultations about the biggest East-West standoff since the Cold War.

"There is no single plan," RIA Novosti quoted Russia's Deputy Foreign Minister Sergei Ryabkov as saying. "We have differing views of the situation. Our discussions involve an exchange of ideas, but one cannot say that we have some sort of single approach."

U.S. Secretary of State John Kerry will meet Russian Foreign Minister Sergei Lavrov for talks on the Ukraine crisis on Sunday, State Department spokeswoman Jen Psaki told reporters.

"The meeting is in Paris tomorrow evening," she said after Kerry left Riyadh early on Saturday, due to fly home to Washington via a refueling stop in Ireland. But Kerry decided mid-flight to go to Paris instead.

Boxer turned opposition leader Vitali Klitschko on Saturday dropped out of Ukraine's snap presidential polls to help the candidacy of a charismatic tycoon who made a fortune selling chocolates and backs closer Western ties.

The towering sports star's decision leaves the crisis-hit nation of 46 million with two clear frontrunners in the May 25 vote -- business baron Petro Poroshenko and the highly divisive and corruption-stained opposition leader Yulia Tymoshenko.

Crimea's Tatars will on Saturday hold a vote on whether to push for self-rule in their historic homeland following its annexation by Russia.

Ethnic Tatars from all over Crimea convened in the town of Bakhchisaray for an emergency Qurultai, or congress, to decide on the fate of the Muslim community of about 300,000 people on the Black Sea peninsula.