Xinhua world news summary at 0030 GMT, June 13

U.S. President Barack Obama on Sunday called the mass shooting at a gay nightclub in Florida earlier in the day an "act of terror" and "act of hate."

At least 50 people were killed and 53 others wounded, including a police officer, early Sunday in the shooting at the popular gay nightclub Pulse in Orlando, Florida. It is the deadliest terror attack in U.S. history since the 9/11 terror attacks in 2001. (U.S.-Florida Shooting)

- - - -

CAIRO/DAMASCUS -- The Islamic State (IS)-linked news agency Amaq said on Sunday that the Islamist militant group was responsible for the shooting that killed at least 50 people at a gay nightclub in Orlando, Florida.

"The attack that targeted a nightclub for homosexuals in Orlando, Florida and left more than 100 dead and wounded was carried out by an Islamic State fighter," said Amaq in a short English statement that went online Sunday evening. (IS-Orlando Shooting)

- - - -

ISLAMABAD -- Pakistan's top foreign affairs adviser, Sartaj Aziz, said on Sunday that senior U.S. officials, who visited Pakistan on Friday, could not explain logic behind the recent drone strike in Balochistan province that killed the Afghan Taliban chief, Mullah Akhtar Mansoor.

American security officials and diplomats visited Pakistan amid growing tensions caused by the May 21 drone attack that Pakistan insists also undermined the diplomatic efforts to start the peace talks in Afghanistan. (Pakistan-U.S.-Drone attack )

- - - -

LONDON -- A government guarantee that protects pensions for millions of elderly people would be under threat if Britain quits the EU, Prime Minister David Cameron warned Sunday.

A so-called triple-lock guarantee has been government policy since 2010, ensuring an annual above-inflation rise in state pensions.(Brexit-Pension) Endi