German Chancellor Angela Merkel will welcome Obama as well as heads of state from Britain, Japan, France, Italy and the European Union for talks, the formal purpose of which is trade. But the issues of Ukraine, including Russia's annexation of Crimea, and the strategy against the Islamic State group are expected to dominate the discussions.

　　Some G-7 nations are participating in allied bombing raids against the Islamic State group, and the fighters’ recent capture of Ramadi in Iraq has left many wondering whether Obama’s strategy is working.

　　Obama to Focus on Russia, Islamic State at G-7

　　Biggest issue: Russia

　　The biggest issue, however, is Russia — excluded from the meeting for a second year. Russia had been part of what was known as the Group of Eight since 1998, but was expelled  last year over its activities in Ukraine.

　　There are questions here about the U.S. leader’s approach to Russia, one that White House officials, including spokesman Josh Earnest, acknowledge has not changed Russian President Vladimir Putin’s behavior in Ukraine.

　　“The economic pressure that's been applied to Russia has not yet resulted in President Putin changing his strategic calculus inside of Ukraine," Earnest said.

　　"We continue to see the Russian military violate the sovereignty and territorial integrity of Ukraine. We continue to see the movement of materiel and personnel across the Ukrainian border in support of Russian-backed separatists in Ukraine," he added.

　　The United Nations is urging all sides in the Ukraine conflict to fully respect the cease-fire agreement reached earlier this year in Minsk.

　　"We are either looking at a return to a deepening, intractable conflict or a momentary upsurge in parts of the conflict zone, " U.N. political chief Jeffrey Feltman told an emergency Security Council meeting Friday.