At 21:08 local time police received multiple calls about a shooting outside an event at the Capital Jewish Museum in downtown Washington DC.

A man and a woman were found unconscious and not breathing at the scene, and later died.

The Metropolitan Police Department (MPD) said the couple were leaving the event at the museum in 3rd St NW – an area with numerous tourist sites, museums and government buildings, including the FBI’s Washington field office.

Police believe the shooting was committed by Elias Rodriguez, 30, of Chicago, who is being questioned in custody.

MPD chief Pamela Smith said he was seen pacing up and down outside the museum before approaching a group of four people and opening fire with a handgun,

The suspect then entered the museum, where he was detained. He then chanted “free, free Palestine” while in custody, police said.

MPD are leading the investigation. The FBI said it is looking into “ties to potential terrorism or motivation based on bias-based crime or a hate crime”.

Witnesses described the aftermath of the attack outside the Capital Jewish Museum.

“At around 09:07 we heard gunshots, and then a guy came in and seemed really distressed and we thought he just needed help and he needed safe shelter,” Katie Kalisher said.

Yoni Kalin, who was also at the event, said: “So people were calming him down, giving him water, taking care of him. Little did we know he was somebody that executed people in cold blood.

“He was the shooter. Once the police originally showed up, he’s like ‘I did this. I’m unarmed.’

“He pulls out a red kaffiyeh and he was like, ‘I did this for Gaza. Free Palestine. There’s only one solution. Intifada revolution’, and he just kept yelling ‘free Palestine’.”

The event at the Capital Jewish Museum was billed as a cocktail evening for young Jewish professionals to foster unity and celebrate Jewish heritage.

The organiser, American Jewish Committee, said it was open to those in the DC diplomatic community. The event’s theme was advertised as “turning pain into purpose”.

The event description said it invited humanitarian aid organisers responding to humanitarian crises in the Middle East, including Gaza.

The event’s hours were publicly advertised. Its location was only shared with those who signed up to attend.

Prime Minister Benjamin Netanyahu said he was was “outraged by the horrifying antisemitic murder” of the victims.

“My heart grieves for the families of the young beloveds, whose lives were cut short in a moment by an abhorrent antisemitic murderer,” he said.

“I have directed that security be increased at Israeli missions around the world and for the state’s representatives.”

Israeli ambassador to the US Leiter said: “We are a resilient people… Together we won’t be afraid, together we’ll stand and we’re going to overcome moral depravity of people who think they’re going to achieve political gains through murder.”

He said Trump told him his administration would do everything it can to fight antisemitism.