A police officer was stabbed and an alleged assailant was reportedly shot after gunfire broke out at the UK Parliament in London on Wednesday.
London police said on Twitter they are treating the attack "as terrorist incident until we know otherwise."
At least four people were lying on the ground, some bleeding heavily, on Westminster Bridge near Britain's parliament, Reuters reported. It was not clear exactly what happened or how many people were injured.
A car on Westminster Bridge has just mowed down at least 5 people. pic.twitter.com/tdCR9I0NgJ
— Radosław Sikorski (@sikorskiradek) March 22, 2017
Reports say they have been run over.
Police said they were called to Westminster at around 10:40 a.m.
The leader of the House of Commons said a man had been shot by police. David Liddington also said there were "reports of further violent incidents in the vicinity."
This is the moment Parliament was suspended as "sounds similar to gunfire" were heard outside pic.twitter.com/to6PPxkNqL
— Sky News (@SkyNews) March 22, 2017
Lidington said the Parliament complex is in lockdown.
BBC News reports police believe there is a suspect vehicle outside parliament, people being evacuated from the area.
Reports of shots outside #UK Parliament. Remain vigilant , exercise caution, and monitor local news for updates.
— Travel - State Dept (@TravelGov) March 22, 2017
Witnesses on scene said about a dozen people were injured on the Westminster Bridge. Another witness told Sky News that there was an "almighty crash" as a vehicle hit the railings outside Parliament.
A witness told Sky News: "Someone rushed through, attacked a policeman... he appeared to be carrying a knife. We heard lots of gunfire."
Witness Jayne Wilkinson told the Telegraph: "We were taking photos of Big Ben and we saw all the people running towards us, and then there was an Asian guy in about his 40s carrying a knife about seven or eight inches long."
Commons speaker John Bercow suspended the session as police responded to an incident.
White House press secretary Sean Spicer said on Twitter that President Trump had been briefed on the ongoing situation.
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."
Prime Minister Theresa May is safe, a spokesperson told reporters.
George Eaton, a journalist with the New Statesman, said that from the window of Parliament's Press Gallery, he saw police shoot a man who charged at officers.
"A large crowd was seen fleeing the man before he entered the parliamentary estate," he wrote on the publication's website. "After several officers evaded him he was swiftly shot by armed police."