President Barack Obama will introduce a raft of executive actions to try to reduce U.S. gun violence Tuesday, bypassing Congress and launching a bitter 2016 election year fight.

Kicking off his last year in the White House with a defiant show of executive power, Obama will ignore Congressional opposition and take a series of unilateral steps to regulate gun sales and curb illicit purchases.

President Barack Obama met late Friday with families of the victims of the San Bernardino shooting, saying they represent the strength, unity and love that exists in the United States.

Obama, who was accompanied by his wife Michelle, also praised the relatives for efforts to promote tolerance in the wake of the attack.

President Barack Obama admitted that "lone wolf" jihadist attacks present a vexing new security challenge Friday, even as he assured Americans the Islamic State group can be defeated.

Obama capped a week in which he has tried repeatedly to reassure a jittery Americans that his administration can neutralize the terror threat, with an end-of-year press conference that only underscored the tough task ahead.

U.S. President Barack Obama sought to reassure terror-struck Americans that the Islamic State group will be defeated Sunday, in a rare primetime address from the Oval Office.

Facing doubts about his leadership, Obama harnessed the highest trappings of U.S. power to calm a nation put on edge by a rampage in California that killed 14 Americans.

President Barack Obama insisted that the United States "will not be terrorized" and renewed his call for tighter gun control measures in a weekly address Saturday that focused on the deadly attack in California.

As it became increasingly likely that the San Bernardino shooting spree that left 14 people dead was inspired by the Islamic State group, Obama vowed that investigators would "get to the bottom" of how and why the rampage occurred.

U.S. House Republicans voted Tuesday to block President Barack Obama's regulations on reducing greenhouse gas emissions -- a move certain to spark his veto -- as negotiators work on a global climate deal in Paris.

The two measures, rolling back the Environmental Protection Agency's new emission rules for power plants, passed the chamber largely along party lines.

U.S. President Barack Obama called on Russia and Turkey to move beyond a furious row over the downing of a fighter jet and focus on the Islamic State jihadist group, after meeting his Turkish counterpart in Paris on Tuesday.

Relations between Moscow and Ankara have plummeted in the past week after Turkey downed a Russian fighter jet along the Syrian border.

U.S. President Barack Obama pushed Monday for a "de-escalation" of a furious war of words over Turkey's downing of a Russian warplane, a White House official said.

Obama called for an easing of inflamed Russia-Turkey tensions in a closed-door meeting with Russia's Vladimir Putin on the sidelines of a climate summit in Paris, the official said.

U.S. President Barack Obama Thursday delivered a Thanksgiving message in which he compared modern refugees to the pilgrims whom the holiday celebrates, urging Americans to open their arms to the potential immigrants.

"Nearly four centuries after the Mayflower set sail, the world is still full of pilgrims -- men and women who want nothing more than the chance for a safer, better future for themselves and their families," Obama said in his weekly address, referring to the boat on which the pilgrims arrived in the New World.

U.S. President Barack Obama called Sunday for resolve in the face of heightened jihadist threats, insisting panicked citizens must not succumb to fear and urging world leaders not to abandon a climate summit in Paris.

With Brussels in lockdown, cities from Beirut to Bamako reeling from attacks, and Americans jittery that they too may come under assault, Obama said the world must show steel.