Ahead of May presidential elections, former Ukrainian Prime Minister Yulia Tymoshenko says "Crimea is Ukraine." (Reuters)

Hoping to defuse the diplomatic crisis with Russia over its annexation of Crimea from Ukraine, Secretary of State John F. Kerry is to meet with his Russian counterpart this weekend, State Department spokeswoman Jen Psaki said Saturday.

Kerry canceled plans to return to the United States from Saudi Arabia on Saturday and instead was headed to Paris for a meeting with Russian Foreign Minister Sergei Lavrov on Sunday evening, Psaki said from a refueling stop here. The goal is to reach agreement on what happens next over Ukraine, following up on a phone call Friday between Russian President Vladimir Putin and President Obama.

The meeting will take place ahead of a gathering of NATO foreign ministers in Brussels on Tuesday and Wednesday that is expected to be dominated by questions about Ukraine and the Russian intervention.

Putin and Obama agreed that Kerry and Lavrov should meet as a step toward resolving an increasingly bitter war of words and economic sanctions.

Although the United States refuses to recognize Crimea’s inclusion in Russia, the diplomatic efforts are aimed primarily at preventing future conflict. U.S. officials have tacitly acknowledged that the Crimea move will not be reversed anytime soon and have focused instead on warning Russia not to move farther into Ukraine.

The United States hopes that an agreement with Russia could set the stage for better relations between Moscow and the Ukrainian government in Kiev. Ukraine has shifted strongly toward Europe and away from Russia since the Russian incursion and the vote in Crimea to leave Ukraine, followed by Russian annexation.

Speaking on Russian television Saturday, Lavrov said Russia had no designs on eastern Ukraine, reinforcing signals from Putin that Moscow would settle, at least for now, for control over Crimea despite massing tens of thousands of troops near the Ukrainian border.

“We have absolutely no intention of — or interest in — crossing Ukraine’s borders,” Lavrov said.

Also Saturday, the Ukrainian former boxing champion Vitali Klitschko announced that he has decided not to run for president and will instead support billionaire businessman Petro Poroshenko, the Associated Press reported.

Klitschko told a congress of his UDAR party Saturday that he plans to run for mayor of Kiev.