OUISTREHAM, France -- Russian President Vladimir Putin spoke face-to-face with Ukraine's incoming president about ending the violence in the former Soviet state, and Kiev's new leader said talks could begin in earnest as soon as Sunday -- a diplomatic breakthrough playing out along the battlefield beaches of Normandy.

Friday's 15-minute meeting was followed by a brief exchange between Putin and President Barack Obama, who had been keeping the Russian at arm's length over the Ukrainian crisis. Tensions between the two were played out on giant televisions on Ouistreham's Sword Beach, with Putin and Obama shown divided by split screens as they commemorated the 70th anniversary of D-Day.

Speaking after his meeting with Petro Poroshenko -- who is to be sworn in Saturday as Ukraine's president -- Putin called for an immediate cease-fire in eastern Ukraine before any further talks, and said he expected Poroshenko to show "state wisdom" and "good will." Poroshenko later said talks could begin in earnest on his first full day in office.

"All the questions were difficult," Poroshenko said in a statement to The Associated Press before returning to Ukraine, "but we will make every effort to achieve the goals we have set ourselves and begin negotiations on Sunday."

Putin said he welcomed Poroshenko's call for an end to the bloodshed and liked his approach to settling the crisis but wanted to wait until the Ukrainian leader could deliver it in detail to the nation.

"If it continues like that, then conditions will be created for developing our relations in other areas, including the economy," Putin said. He specified that Moscow is ready to lower gas price for Ukraine if it pays off its debt for previous supplies, easing fears of a gas shutdown to Europe dependent upon gas pipelines that cross Ukraine.

French President Francois Hollande, who orchestrated the meeting along with German Chancellor Angela Merkel, said Putin and Poroshenko also discussed how Russia could recognize the Ukrainian elections as well as measures to de-escalate the fighting.

"It didn't last a long time but long enough for the message to be passed on," Hollande told the French network TF1.

Putin's spokesman Dmitry Peskov said that Putin and Poroshenko also "confirmed that there is no alternative to settling the situation by peaceful political means."

Frozen out of G-7 talks Thursday in Brussels, Putin appeared to be moving incrementally back into the fold of the West following his first direct talks with Poroshenko since the billionaire was elected to lead Ukraine. The previous pro-Kremlin president, Viktor Yanukovych, was ousted in what Putin said was a coup.

Russia, which had recalled its ambassador from Ukraine, said he will return to Kiev to attend Poroshenko's inauguration. That appeared to be a recognition of Ukraine's election, Hollande said.

Putin has denied allegations by Kiev and the West that Russia has fomented the rebellion, and he insisted Friday that Poroshenko needs to speak directly to representatives from the east. He didn't say if Moscow was prepared to take any action to persuade the insurgents to stop fighting Ukraine's government troops.

Obama, who said he has a "businesslike" relationship with Putin, expressed hope that the Russian leader is "moving in a new direction" on Ukraine by not denouncing Poroshenko's May 25 election. "But I think we have to see what he does and not what he says," Obama said.

The anniversary of the D-Day invasion in 1944 -- a time when the U.S., Britain and Russia were allied against Nazi Germany -- marked the best opportunity for the leaders to meet since the crisis in Ukraine began. Merkel's key role appeared to endure through the ceremony in Ouistreham, in an extraordinarily symbolic sign of Germany's changed role in Europe.

At least 15 pro-Russian rebels were killed Thursday in clashes with government troops at a Ukrainian border crossing with Russia, an aide to Ukraine's interior minister said.

Speaking on a TV show, Anton Herashchenko said armed men came from Russia in trucks and an infantry vehicle and tried to cross the border at the village of Marynivka and were supported by 100 rebels from the Ukrainian side. His report of casualties could not be confirmed independently.

Following the clash, Ukraine's government ordered the closing of parts of the border with Russia, including the Marynivka crossing, to try to prevent armed men from infiltrating. The Russian Foreign Ministry said it was "outraged" by the move.