President Barack Obama on Thursday met survivors of a massacre at an Orlando gay nightclub and relatives of the 49 people killed 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, 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.