U.S. President Barack Obama hit back at foreign policy critics in an interview aired Sunday, brushing off claims he had been naively outmaneuvered by Russian counterpart Vladimir Putin over the Ukraine crisis.

North Korea's alleged hack of Sony Pictures was not an act of war, President Barack Obama said in an interview aired Sunday, as Pyongyang threatened reprisals if targeted with sanctions. 

Obama's Republican critics have accused North Korea of waging "cyber warfare" by targeting Sony, urging the president to respond robustly to the crisis.

The latest round of Ukraine-related sanctions by the United States and Canada hamper efforts to resolve the conflict, Russia's foreign ministry said Saturday.

"The sanctions are directed to disrupt the political process," the ministry said in a statement following the announcement of the latest measures on Friday. 

President Barack Obama has -- in just a few weeks and in spectacular fashion -- turned the tables on U.S. policy toward Latin America, neglected by Washington for much of this century.

While campaigning in 2008, Barack Obama said it was time to come up with a new U.S. policy towards Cuba. Now, with two years left in his second term in the White House, he has finally acted.

The president has broken with a half century of seeking to isolate Cuba by announcing plans to restore diplomatic relations with the communist-run island after a year and a half of secret negotiations.

Barack and Michelle Obama have revealed their experiences of racism in a wide-ranging interview with celebrity weekly People Magazine published Wednesday.

The United States and Cuba brought their bitter Cold War stand-off towards a historic close Wednesday, agreeing to revive diplomatic ties and to ease a five-decade U.S. trade embargo.

In the wake of a prisoner exchange, President Barack Obama said Washington is ready to review trade ties and to re-open its embassy in communist Cuba, which has been closed since 1961.

The U.S. Senate confirmed Tony Blinken as deputy secretary of state on Tuesday, installing a seasoned insider who has served as a close advisor to President Barack Obama.

Blinken, the outgoing deputy national security advisor, was confirmed on a vote of 55-38, becoming Secretary of State John Kerry's number two.

U.S. President Barack Obama will sign into law a bill passed by Congress to tighten sanctions against Russia over its actions in Ukraine, the White House said Tuesday, amid a dramatic run on the ruble.

U.S. President Barack Obama condemned the deadly Taliban raid on a Pakistani school Tuesday and promised that America would stand by the country in its struggle against violent extremism.

"By targeting students and teachers in this heinous attack, terrorists have once again shown their depravity," he said, after the attack on the army-run facility in Peshawar left at 130 people dead.