Police in London are responding to what they're calling "a terror incident," when a man reportedly attacked a police officer with a knife at Parliament before he was shot by officers.
Four people have been killed, and an unknown number of others have "catastrophic" injuries as a result of the attack.
The House of Commons was on lockdown, while the press office for Prime Minister Theresa May confirmed that she was "safe and at work."
Matthew Rozsa is a breaking news writer for Salon. He holds an MA in History from Rutgers University-Newark and is ABD in his PhD program in History at Lehigh University. His work has appeared in Mic, Quartz and MSNBC.