The White House on Monday announced that President Barack Obama will visit Orlando, Florida on Thursday to mourn the victims killed in the deadliest shooting in U.S. history.

"On Thursday, the president will travel to Orlando, Florida to pay his respects to victims' families, and stand in solidarity with the community as they embark on their recovery," said a White House statement.

Obama's trip will come four days after a gunman shot dead 49 people and injured 53 more at a gay nightclub in Orlando, Florida.

The gunman, identified as Omar Mateen of Port St. Lucie, Florida, was found dead inside the nightclub after a shootout with police.

After his meeting with Director of Federal Bureau of Investigation James Comey on Monday, Obama told reporters that the Florida shooting was "homegrown extremism."

"As far as we can tell right now, this is certainly an example of the kind of homegrown extremism that all of us have been so concerned about for a very long time," said Obama at the White House.

According to Obama, so far there was no "clear evidence" that the gunman had been directed externally.

"It does appear that at the last minute, he announced allegiance to ISIL," said Obama, referring to an acronym of the extremist group the Islamic State (IS) based in Syria and Iraq. "But there's no evidence so far that he was, in fact, directed by ISIL."

IS-linked news agency Amaq said on Sunday that the Islamist militant group was responsible for the shooting.

"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.

source : xinhua