At least a dozen people were injured in a shootout outside the British Parliament on Wednesday, as per initial reports in the BBC. The Palace of Westminster was put under lockdown even as the assailant was shot by security forces, said a minister.
Initially two people were reportedly shot outside the Parliament building in London, United Kingdom (UK).
An eyewitness said he heard shots being fired and saw two people apparently injured on the ground.
The House of Commons session has been suspended and the Palace of Westminster has been put on lock down, an official said.
A spokesperson for the government said Prime Minister Theresa May is safe after the attack.
A Reuters photographer also reported seeing at least 12 injured people on Westminster Bridge near the Parliament.
David Lidington, leader of the House of Commons, said that the alleged assailant was shot outside the Parliament building by armed police.
The Metropolitan Police said the incident on Westminster Bridge is being treated as a terrorist incident until investigation indicates otherwise.
Britain's MI5 said it is too early to say if the incident is terror-related.
Parliament Square was closed to traffic and air ambulance medics have arrived to assist the casualties.
Britain is on its second-highest level of "severe", meaning an attack by terrorists is considered highly likely.
The incident took place on the first anniversary of attacks on Brussels in Belgium.