THE HAGUE, Neatherlands -- President Barack Obama vowed Tuesday that the United States would use its military to come to the defense of any NATO country that is threatened, sending a warning to the Russia's President Vladimir Putin about the consequences of further aggression along the border with Eastern Europe.
"We will act in their defense against any threats," Mr. Obama said at a news conference in The Hague. "That's what NATO is all about. When it comes to a potential military response, that is defined by NATO membership."
The president said the United States and other world powers rejected Russia's annexation of Crimea, a region of Ukraine that voted to secede on March 16. But he acknowledged that military force would not be used to return that region to Ukraine, which is not a member of NATO.
"There's no expectation that they will be dislodged by force," Mr. Obama said of the Russian forces in Crimea.
He said the world was limited to trying to use legal and economic pressure against Russia, saying, "It would be dishonest to suggest that there is a simple solution to resolving what has already taken place in Crimea."
But Mr. Obama quickly added, "History has a funny way of moving in twists and turns, and not just in a straight line."
Meanwhile, Ukraine's parliament accepted the resignation of the country's defense minister Tuesday as Ukrainian troops were carrying out a painful withdrawal from Crimea, the peninsula now in Russian hands.
In Parliament, outgoing Defense Minister Ihor Tenyukh was criticized by some lawmakers for giving up Crimea without battling back against Russian forces.
On another matter at his news conference, Mr. Obama also said his plan to let bulk telephone data records remain in the hands of communications companies would allow the U.S. government to effectively combat terrorism while eliminating concerns that law enforcement could abuse the database to invade people's privacy.
A day after leading a meeting of the industrialized democratic nations known as the Group of Eight until Monday, when members voted to oust Russia, Mr. Obama accused Mr. Putin of acting from a position of weakness in Russia's aggression against Ukraine.
"The fact that Russia felt compelled to go in militarily," Mr. Obama said, "indicates less influence, not more."
The president said Russia's buildup of troops on its border with Ukraine appeared to be "intimidation," while acknowledging that "Russia has a right legally to have its troops on its own soil."
But Mr. Obama rejected an assertion made during the 2012 presidential campaign by Mitt Romney, his Republican challenger, that Russia would be the "No. 1 geopolitical foe" for the United States in the years ahead. He said Russia was largely a threat to its neighbors, not to the United States.
Los Angeles Times contributed