"The thoughts of the men and women of MI5 are with the families of those killed in Westminster yesterday, and with the other innocent people injured in this appalling and disgusting attack. We stand shoulder-to-shoulder with our police colleagues, grieving at their loss while also applauding the professional excellence of their response. The MI5 operational response is fully mobilised in support of the police," the statement said.
On Wednesday, an attacker hit several people while driving on Westminster Bridge in the UK capital. Armed with a knife, he then attempted to enter the parliament, stabbing a police officer to death in the process. The assailant was shot by police and later died in a hospital. According to London Metropolitan Police Acting Deputy Commissioner Mark Rowley, four people, including the attacker, were killed in the terrorist act, while at least 40 people were injured.