Australian Prime Minister Tony Abbott on Saturday urged Scotland to stay in the United Kingdom, saying independence would be cheered by enemies of justice and freedom.

Abbott's comments to The Times newspaper are the strongest given yet by a major foreign leader on the Scottish independence debate, and follow on from calls from U.S. President Barack Obama to keep the union intact.

U.S. President Barack Obama will go to Estonia next month to reaffirm Washington's commitment to NATO allies at a time of rising tensions with Russia over Ukraine, the White House announced Friday.

"In light of recent developments in Ukraine, the United States has taken steps to reassure allies in Central and Eastern Europe, and this trip is a chance to reaffirm our ironclad commitment to Article V as the foundation of NATO," the White House said.

President Barack Obama declared Thursday that U.S. air strikes had broken the siege of an Iraqi mountain sheltering civilian refugees and that troops conducting reconnaissance there would be withdrawn.

But he added that U.S. air strikes would continue against extremists from the so-called Islamic State or ISIL if they threaten U.S. personnel and facilities in the region, including the Kurdish regional capital Arbil.

With no set timescale for military engagement and few certainties in Baghdad's political crisis, U.S. President Barack Obama's week-old Iraq intervention threatens to monopolize the rest of his presidency.

Two-and-a-half years after he oversaw the withdrawal of U.S. troops from Iraq, Obama has ordered airstrikes against a jihadist group but has vowed that America will not be drawn into ground combat.

Hillary Clinton's relationship with President Barack Obama is entering a potentially awkward new era as the former U.S. secretary of state eyes a possible 2016 bid for the White House.

After a ferociously bitter battle with Obama for the 2008 Democratic presidential ticket, Clinton was a loyal lieutenant in the president's first administration before she stepped down in 2013.

Hillary Clinton may have distanced herself from Barack Obama's foreign policy, but he doesn't seem to have taken it personally: the two will meet at a party later this week.

Obama and the presumptive frontrunner for his Democratic Party's 2016 presidential nomination are due to attend the same soiree on Martha's Vineyard on Wednesday.

President Barack Obama called Robin Williams "one of a kind" who shared his talent "freely and generously with those who needed it most."

Williams was pronounced dead at his home in California Monday and officials said it appeared to be a suicide.

Former secretary of state Hillary Clinton blamed the rise of Islamist militants in Iraq and Syria on failures of U.S. policy under President Barack Obama, in an interview published Sunday.

Clinton specifically faulted the U.S. decision to stay on the sidelines of the insurgency against Syria's President Bashar Assad as opening the way for the most extreme rebel faction, the Islamic State.

The United States carried out new air strikes and aid drops Saturday, as President Barack Obama vowed to help rescue thousands of civilians besieged by jihadists on an Iraqi mountain.

Any "humanitarian" mission by Russia into Ukraine would be "unjustified and illegal", U.S. President Barack Obama and British Prime Minister David Cameron agreed during a telephone call Saturday, Downing Street said.

"On Ukraine, both expressed grave concern about reports that Russian military vehicles have crossed the border into Ukraine and that Russian armed forces are exercising for a 'humanitarian intervention,'" a statement from Cameron's office said.