Obama meets Orlando massacre survivors, assails homegrown terrorism

"The last two terrorist attacks on our soil - Orlando and San Bernardino - were homegrown," Obama told reporters, before urging Congress to pass measures to make it harder to legally acquire high-powered weapons like the assault rifle used in the attack on Sunday.

"I'm pleased to hear that the Senate will hold votes on preventing individuals with possible terrorist ties from buying guns," he said.

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

New details emerged on Thursday about the gunman's activity on Facebook and text messages he sent during the shooting rampage.

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

Islamic State claimed responsibility for the attack but U.S. 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.