Four people died and at least 20 others were injured Wednesday when a man rammed into several pedestrians on London’s Westminster Bridge before attacking a police officer stationed outside the British Parliament, police said. >> Read more trending news Mark Rowley, national head of counter-terrorism and policing for London metropolitan police and acting deputy commissioner, said the attacker and a police officer who he stabbed were among those killed. Police were called at 2:40 p.m. GMT to respond to reports of a “firearms incident” at the bridge, just down the street from Parliament’s home at the Palace of Westminster, London metropolitan police said. Here’s what we know so far: Officials believe that a man mowed down several pedestrians on Westminster Bridge before stabbing a police officer who was guarding the Parliament building. The attacker crashed near Parliament before getting out of the car armed with a knife and attacking the officer, Rowley said. Police opened fire on the man, killing him. The stabbed police officer died as a result of the attack, Rowley said. The officer’s family has been notified, although police did not immediately release the officer’s identity. Police Cmdr. B.J. Harrington said authorities got multiple calls about the incident, including one about a woman in the River Thames. Authorities believe that she might have been on the bridge during the attack. She was pulled from the water alive and was being treated by paramedics, according to ITV News. “Five people in total have died” and at least 40 people were injured in the attack, Rowley said. In a news conference Wednesday at 10:26 p.m. GMT, Rowley offered more infomation on the deaths and injuries. “One of those who died was a police officer from our Parliamentary and Diplomatic Protection Command who had 15 years of service,” Rowley said. “Three members of the public also lost their lives in this attack. Specially trained officers will support them.” “The suspected attacker was shot dead by an armed officer, meaning five people in total have died,” he said. Those injured in the bridge attack included three police officers who were on the way back from a commendation ceremony. “At this stage -- but it may change -- we believe approx 40 people were injured including three police officers,” Rowley said at the news conference. French Prime Minister Bernard Cazeneuve confirmed on social media that French students were also among the injured. The students, between 15 and 16 years old, were visiting from Concarneau High School in Brittany, French newspaper Le Telegramme reported. The London Ambulance Service said it treated at least 10 people for injuries on the bridge. An unidentified doctor who responded to the incident on the bridge told Britain’s Channel 4 News that those who were injured when the attacker’s car rammed several pedestrians suffered a variety of injuries. Authorities are treating the incident as terrorist-related “until we know otherwise,” police said. An unidentified European security official told The Associated Press that chatter increased Tuesday on jihadi networks in response to the United Kingdom’s decision to ban electronics aboard flights from some Muslim-majority countries. The United States has adopted a similar measure. The official told the wire service that there were no early indications that Wednesday’s attack was terror-related. “Our investigation is continuing and is moving at a fast pace this evening - we will work through the night,” Rowley said. The attack took place on the one-year anniversary of the deadly Brussels Airport bombing. >> Related: Brussels terror attacks: What we know now President Donald Trump has been briefed on the situation, White House press secretary Sean Spicer said. American officials are monitoring the situation. British Prime Minister Theresa May has condemned the “sick and depraved” attack, The Associated Press reported. In her statement about the attack, she said tomorrow will go on as normal. Tomorrow morning, Parliament will meet as normal. We will come together as normal. And Londoners – and others from around the world who have come here to visit this great City – will get up and go about their day as normal. They will board their trains, they will leave their hotels, they will walk these streets, they will live their lives. And we will all move forward together. Never giving in to terror. And never allowing the voices of hate and evil to drive us apart.