London: The U.S. State Department says it is closely monitoring the incident outside London's Parliament and urged Americans in London to avoid the area.
Spokesman Mark Toner said Wednesday: "We stand ready to assist in any way the U.K. authorities would find helpful."
He added that the U.S. Embassy in London is closely following the news and stands ready to help any affected Americans. "Our hearts go out to those affected."
The White House says U.S. President Donald Trump has been briefed on a gun and knife incident at Britain's Parliament in London. Trump himself said during a brief appearance Wednesday before reporters at the White House that he was just getting the news. He called it "big news."
Trump's spokesman, Sean Spicer, says the U.S. will continue to monitor the situation and update the president. Britain's Parliament was on lockdown after - according to officials - an assailant stabbed an officer then was shot by police.
London Police also said officers were called to an incident on nearby Westminster Bridge.