British Prime Minister David Cameron said on Friday that growing evidence of the use of chemical weapons by the Syrian regime was "extremely serious".

He agreed with U.S. President Barack Obama that such use would represent a "red line" for the international community, but said the response would likely be political rather than military.

U.S. President Barack Obama has a unique strategy for keeping his daughters from getting tattoos: threatening to get the same design, along with his wife, and turning it into a family YouTube moment.

"What we've said to the girls is: 'If you guys ever decide that you're going to get a tattoo, then mommy and me will get the exact same tattoo, in the same place," Obama explained on NBC's "Today" show on Wednesday.

Hackers spooked markets Tuesday after breaking into the Associated Press's Twitter account and falsely reporting President Barack Obama had been injured after two blasts at the White House.

A brief alert on the news agency's @AP account read: "Breaking: Two explosions in the White House and Barack Obama is injured."

Turkish Prime Minister Recep Tayyip Erdogan on Tuesday said he would go ahead with a scheduled trip to the Gaza Strip in May despite U.S. calls to delay the visit.

"There is no question of delaying this trip," Erdogan said on Turkish television.

Russia and the United States agreed Saturday to step up cooperation in their fight against terror in the wake of news that two ethnic Chechens were suspected of organizing the deadly Boston Marathon bombings.

The Kremlin said Russian leader Vladimir Putin called U.S. President Barack Obama to once again express his condolences and discuss ways the two sides can work more closely on security in the runup to the 2014 Winter Olympic Games in Sochi.

U.S. police on Friday captured an ethnic Chechen teenager suspected of staging the Boston Marathon bombings, after a desperate manhunt that virtually paralyzed the city and its suburbs.

Responding to a tip from a local resident, police found Dzhokhar Tsarnaev, 19, hiding in a boat in a suburban backyard in Watertown, wounded and weary after a gun battle overnight in which his accomplice brother was killed.

A 45-year-old man suspected of sending poison-laced letters to President Barack Obama and a U.S. senator has been charged with threatening the life of the president, authorities said Thursday.

Paul Kevin Curtis was arrested Wednesday by the FBI at his home in Corinth, Mississippi, and was due to appear in court Thursday. If convicted, he faces up to 15 years in prison and $50,000 in fines, prosecutors said.

U.S. President Barack Obama vowed Thursday that the Boston marathon bombers would be found and held "accountable" as investigators focused their efforts on two potential suspects.

"Yes, we will find you, and yes, you will face justice," Obama told a special service in the city, three days after the two bombs killed three people and injured about 180 in a hail of nails and ball bearings.

U.S. Defense Secretary Chuck Hagel declined Wednesday to discuss Syria's possible use of chemical weapons against rebels, raising doubts over whether Washington still views such action as a "red line."

President Barack Obama has repeatedly warned Damascus against resorting to chemical weapons, hinting that the use of such arms or the prospect of militant groups gaining control of them could prompt a U.S. military intervention.

President Barack Obama's push for tighter gun controls faced defeat after getting blocked in the Senate, while the president, surrounded by shooting victims and families of victims, said the powerful gun control lobby "willfully lied" to the American people.

"All in all, this was a pretty shameful day for Washington," the president said Wednesday evening. "Who are we here to represent?"