One woman has died and other people are being treated for “catastrophic” injuries after an attack near parliament on Wednesday, British news agency Press Association reported, citing a junior doctor at a central London hospital.
According to witness reports, a car also ploughed into several bystanders on the nearby Westminster Bridge before crashing into railings outside parliament.
“Officers – including firearms officers – remain on the scene and we are treating this as a terrorist incident until we know otherwise,” London’s Metropolitan Police said in a statement.
The House of Commons, which was in session at the time, was immediately suspended and lawmakers were asked to stay inside. PrimeMinister Theresa May was safe after the incident, a spokesperson for her office said.
The leader of the House, David Lidington, said in the chamber that an assailant who stabbed a policeman had been shot by police.
An ambulance helicopter landed on Parliament Square, just outside the building. The BBC said police believed there was a suspect vehicle outside parliament but police did not immediately confirm that report.
Amid confusing scenes, it appeared the incident may have unfolded in several locations, including the busy bridge where tourists often congregate to take pictures of Big Ben and other attractions.
The incident took place on the first anniversary of attacks on Brussels in Belgium.
Reuters reporters inside parliament said a large number of armed police, some carrying shields, were pouring into the building.
Britain is on its second-highest level of “severe” meaning an attack by militants is considered highly likely.
In May 2013, two British extremists stabbed to death soldier Lee Rigby on a street in southeast London.
In July 2005, four British extremists killed 52 commuters and themselves in suicide bombings on the British capital’s transport system in what was London’s worst peacetime attack.
US President Donald Trump told reporters at the White House he hadbeen briefed on events in London but gave no details.