Rubio calls killing of 2 Israel Embassy staffers in Washington 'assassination'

US Secretary of State Marco Rubio on Thursday called the killing of two Israeli Embassy staffers in Washington, DC a "horrifying assassination" and linked it to radicalization in the country.

"We have spoken to the Israelis. This is a terrible, horrifying assassination. That's what it was, an assassination of two young -- beautiful couple by a radical," Rubio told reporters before meeting with Spanish Foreign Minister Jose Manuel Albares at the State Department.

A gunman opened fire near the Capital Jewish Museum in the US capital late Wednesday, killing two Israeli Embassy staff members. The suspected gunman shouted: "Free Palestine," as he was taken into custody, according to a video that went viral on social media.

Rubio offered condolences to the victims' families and said the attack highlights a broader threat.

"It just shows you sort of the danger that exists in the radicalization that we have inside our country," he said.