LONDON (CBSNewYork/AP) -- Five people were killed – including a police officer and the attacker – and some 40 more were injured – in a terrorist incident in London Wednesday.
As CBS News' Tina Kraus reported, a vehicle driven by an assailant rammed into a crowd of pedestrians on the Westminster Bridge.
Police said the vehicle then crashed into the gates of Parliament. People were seen running for their lives.
"We just heard a bang and then we just saw three people in the road," an eyewitness said.
As CBS2's Jessica Layton reported, the chaos was captured on cellphone video as the heart of the city – where freedom was celebrated – came under attack.
"There was bodies, literally must have been 10, 12 bodies, lying on different places along the bridge," a witness said.
One woman was confirmed dead and a body was seen lying in the yard of Parliament.
"There were people across the bridge. There were some with minor injuries, some catastrophic," Colleen Anderson of St Thomas' Hospital said. "Some had injuries they could walk away from or who have life-changing injuries.''
Police said the suspect then got out and stabbed a police officer to death before he was shot and killed by police.
A surveillance camera showed the sport-utility vehicle speeding. Moments later, a woman is seen plunging into the Thames River. She survived.
"I heard one guy come running to the police officer that he needs help, that his wife had jumped into the river to avoid being knocked over," said bus driver Michael Adamou.
"A guy came past my right shoulder with a big knife and just started plunging it into the policeman," witness Rick Longley told the Press Association. "I have never seen anything like that. I just can't believe what I just saw.''
The officer who was killed was identified as Keith Palmer. Rowley said the officer was from the Metropolitan Police Parliamenary and Diplomatic Protection Command and had 15 years' service.
According to David Lidington, the leader of Britain's House of Commons, the officer was stabbed inside the gates of the Parliament compound before the suspect was shot, CBS News reported.
PHOTOS: UK Parliament Attack
Among the heroes who rushed in to save lives was a New York City-born member of Parliament – Tobias Ellwood. His hands, sleeves and face were left stained with blood.
Once a captain in the British army, Ellwood's brother was killed by the bombings in Bali in 2002.
London Metropolitan Police Assistant commissioner for Specialist Operations Mark Rowley said Parliament was locked down following the attack. The House of Commons, which was in session at the time, was immediately suspended and lawmakers were asked to stay inside.
Riders on the London Eye also had to stay put.
A search was conducted late Wednesday to make certain there were no other attackers in the area -- though police believed there was only one attacker.
Rowley said the dead police officer was one of the armed officers who guard Parliament. The other victims were on Westminster Bridge.
Rowley said, "We are satisfied at this stage that it looks like there was only one attacker. But it would be foolish to be overconfident early on.''
He added, "Our working assumption is he was inspired by international terrorism."
Metropolitan Police Cmdr. B.J. Harrington said a full counterterrorism investigation was launched.
He said additional police officers, armed and unarmed, will be deployed across London during the evening rush hour as part of efforts to keep people safe.
Numerous witnesses shared graphic and shocking details and images.
The former Polish foreign minister Radek Sikorski, who is a senior fellow at the Harvard Centre for European Studies, posted a video on Twitter that seems to show people lying injured in the road on Westminster Bridge.
Sikorski told the BBC he "heard what I thought what I thought was just a collision and then I looked through the window of the taxi and someone down, obviously in great distress."
"Then I saw a second person down, and I started filming, then I saw three more people down, one of them bleeding profusely,'' he said.
American tourists near the scene of the attacks described what they saw. Visitors to the London Eye said they could tell something was wrong once they got into the air.
"I just saw the bodies on the sidewalk, a lot of people being treated - like eight maybe?" said California tourist Justin Goody.
"We saw ambulances and emergency crews caring for people in several spots," said Boston tourist Ann Hutchinson. "We actually found out through Twitter."
Westminster Bridge is just outside the Palaces of Westminster, which is the home of the Parliament. People began leaving the Houses of Parliament about two hours after the incident.
Britain's Prime Minister Theresa May will chair a meeting of the government emergency committee to discuss the response to the incident.
May offered prayers to the victims and their families "who waved their loved ones off, but will not now be welcoming them home."
The emergency committee known as Cobra coordinates the high-level response to serious incidents. It brings together government ministers with senior officials of the emergency services and security and intelligence agencies.
Investigators had not identified the suspect Wednesday night, but witnesses said the man who drove the car and carried the knife may have been in his 40s.
Scotland Yard worked around the clock late Wednesday to confirm the belief that the attacker acted alone.
Big Ben went dark shortly after midnight local time in commemoration of the victims. The Eiffel Tower also went dark in solidarity with the people of London.
Prime Minister May said Parliament will meet as usual on Thursday.
But Queen Elizabeth II has postponed plans to open the new Scotland Yard on Thursday. Buckingham Palace said the change is due to security concerns.
The terror investigation will occupy many police officers, and extra officers will be deployed to handle enhanced security around London.
Meanwhile, White House Press Secretary Sean Spicer said President Donald Trump was briefed on the incident. He said they will continue to monitor the situation and update the president.
Trump himself said during a brief appearance Wednesday before reporters at the White House that he was just getting the news. He called it "big news.''
Secretary of State Rex Tillerson issued a statement offering his condolences to the victims.
"The American people send their thoughts and prayers to the people of the United Kingdom. We condemn these horrific acts of violence, and whether they were carried out by troubled individuals or by terrorists, the victims know no difference,'' he said.
State Department spokesman Mark Toner said the U.S. was ready to assist in any way.
"The safety and security of U.S. citizens overseas is one of our highest priorities. Our embassy in London is monitoring the situation closely,'' he added.
Extra NYPD officers stood guard outside the Grand Central Terminal, City Hall and the British Consulate, armed with long guns and strict orders to fire on moving vehicles that are used as weapons of terror.
(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)
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