The administration said Russia must "take immediate steps toward de-escalation” in Ukraine.
Russia opposes the trade deal, which Georgia and Moldova also signed.
Nine service members were lost in the attack by pro-Russian separatists.
Treasury Secretary Jack Lew on Thursday urged Russia to take quick action to stop the violence in...
Moscow has threatened to disrupt natural gas flow to Ukraine amid political turbulence.
Obama asked Putin to halt support for separatists in Eastern Ukraine.
French President Hollande is set to have two dinners Thursday — with Putin and Obama.
Obama painted Ukrainians as the heirs of the resistance to communist rule in Poland.
President-elect Poroshenko will be sworn in on June 7.
The Pentagon chief called the moves “promising."
Obama argued for a new breed of foreign policy that prizes diplomacy and multilateralism.
Sen. Bob Corker (R-Tenn.) demanded that Europe stand up for Ukraine after it elected a new...
The U.S. expectation is that Russia would prefer to avoid a hit to its economy.
Kerry said he would prefer that the international community not be in "sanction mode.”
Putin asked Russian lawmakers to revoke his right to use troops in Ukraine.
NATO's secretary-general called it a "regrettable step backwards."
The State Department called the incursion "unacceptable."
Sen. Ed Markey (D-Mass.) on Thursday introduced a bill that would offer Ukraine assistance in...
Putin was reacting to critical comments made by Clinton in the past.
Obama called on leaders in Europe to expand and diversify their energy supplies.
"The forces that had been on the border are returning to their home bases," a spokesman said.
U.S. efforts to rally world against Russia's incursion into Ukraine have "rapidly changed."
Obama called the new Ukrainian leader and urged him to implement reforms.
Pro-Russian separatists have disrupted regions in the east, the senator said.