Full coverage: 50 Dead in Orlando Nightclub Shooting

UNITED NATIONS, June 12 (Xinhua) -- UN Secretary-General Ban Ki-moon on Sunday condemned the "horrific attack" in Orlando in the U.S. state of Florida, in which 50 people were killed earlier in the day.

The secretary-general "extends his deepest condolences to the families of the victims and expresses his solidarity with the government and people of the United States," said a statement issued here by Ban's spokesman.

A gunman wielding an assault-type rife and a handgun killed at least 50 people in a nightclub in Orlando early Sunday in the worst mass shooting in the U.S. history. U.S. President Barack Obama decried the tragedy as an "act of terror."

The Islamic State-linked news agency, Amaq, said the attack was carried out by an Islamic State fighter.