US President Barack Obama (L) and Vice President Joe Biden place flowers at a makeshift memorial for shooting victims of the massacre at a gay nightclub in Orlando, Florida, US, June 16, 2016. [Photo/Agencies]

ORLANDO, Fla.- President Barack Obama met survivors of a gay nightclub massacre and relatives of the 49 people killed on Thursday and said the United States must act to control gun violence and fight what he called homegrown terrorism.

"The last two terrorist attacks on our soil - Orlando and San Bernardino - were homegrown," Obama told reporters. "We're going to have to do more to prevent these kinds of events from occurring. It's going to take more than just our military. It's going to take more than just our intelligence community."

Obama and Vice President Joe Biden arrived in Orlando, Florida, four days after a US-born gunman claiming allegiance to various Islamist militant groups carried out the deadliest mass shooting in modern US history.

The United States has made it too easy for disturbed or wrathful people to legally acquire high-powered weapons like the assault rifle used in the attack on Sunday, Obama said.

"I held and hugged" grieving family members before laying flowers at a memorial for the victims of the attack on the Pulse nightclub, he said. Police killed the gunman, Omar Mateen, 29, a US citizen born in New York to Afghan immigrants.

Islamic State claimed responsibility for the attack but US officials have said they do not believe Mateen was assisted from abroad. CIA Director John Brennan told a Senate Intelligence Committee hearing on Thursday that the agency had "not been able to uncover any direct link" between Mateen and militants abroad.

A married couple also claiming allegiance to Islamic State shot dead 14 people in San Bernardino, California, in December.