Brussels, Sha'ban 7, 1435, Jun 5, 2014, SPA -- Russian President Vladimir Putin has two to four weeks to change tack in Ukraine or face more sanctions, US President Barack Obama said Thursday, amid a whirlwind of European diplomacy aimed at defusing the region's worst crisis since the Cold War; dpa reported. A partial pull-back of Russian troops from Ukraine's border and the fact that Moscow is not "overtly" destabilizing its neighbour "does not mean that we can afford three months or four months or six months of continued violence and conflict in eastern Ukraine," Obama said. He made his comments in Brussels, where the leaders of the Group of Seven (G7) agreed during two days of talks to a common set of demands for Russia, while upholding the threat of sanctions if Moscow further destabilizes the situation in Ukraine. They said Russia must recognize the results of Ukraine's recent elections and cooperate with its new president; withdraw all troops from the border; stop weapons and militants from entering Ukraine; and pressure pro-Russian separatists to give up arms. The international community would be watching what Putin does over the next "two, three, four weeks." Obama added that, "if he remains on the current course," Russia will face "additional costs." G7 nations have targeted individuals and companies in Russia and Ukraine with asset freezes and travel bans for their role in the Ukraine crisis, but so far have shied away from economic sanctions. Such measures would be "more significant," Obama said, adding that US and EU teams had been consulting to identify "sanctions that would maximize impact on Russia and minimize adverse impacts on European countries." Economic sanctions would "inevitably hit Russia a lot worse than it hits Europe," he added. The G7 talks replaced a Group of Eight (G8) summit in Russia that was snubbed by Britain, Canada, France, Germany, Italy, Japan, and the United States because of Moscow's actions in Ukraine. "Russia's actions are completely unacceptable and totally at odds with the values of this group of democracies," said British Prime Minister David Cameron. "That is why Russia no longer has a seat at the table here with us." But despite the post-Cold War lows in Russia's relationship with the West, Putin flew to France on Thursday to take part in World War II commemorations. There, he is to hold the fist face-to-face talks with Western leaders since Russia's annexation of Crimea in March. He will meet French President Francois Hollande and Cameron in Paris late Thursday. Putin will also meet German Chancellor Angela Merkel in Normandy on Friday, where the D-Day ceremonies will take place. Merkel said she would not raise the issue of sanctions with the Russian leader. "It is not about threats," she said in Brussels. "It is about making clear that we want solutions through dialogue." G7 leaders have been intent on speaking with one voice. "I think it's been very striking, actually, over the last few months how we've been able to stay as unified as we have," Cameron said, adding, "I think it surprised people. And I hope it surprised President Putin." Obama has not formally arranged talks in France with the Russian leader, but said he had "no doubt that I'll see Mr Putin." -- SPA 20:57 LOCAL TIME 17:57 GMT www.spa.gov.sa/1240680