Transcript for Police dealing with an 'incident' on London Bridge

This is an ABC news special. A good evening this is an ABC news special report on Tommy Thomas in New York what appears to be a major police emergency unfolding in London tonight. Details just beginning to come in. Reports of violence in several London locations you see them there. We do know the president trump has been briefed on the incidents and is monitoring the situation. In London prime minister Teresa may has also been in contact with security officials here's what we know at this hour an incident happening at the London Bridge. The nearby at a restaurant and oral Paul and also a possible third incident. At boss hall is still unclear exactly what has happened but it comes at a time when European cities are becoming more more frequent targets for terrorists. And England still reeling from the recent suicide bombing in Manchester just two weeks ago. And this just in for more teen in London London Metropolitan Police are asking local radio stations right now to broadcast this message to anyone caught up in any these incidents to quote run. Hide and tell let's go to London right now ABC's Jennifer Michelson start us off tonight Jennifer. Time chaotic and disturbing scenes in 3 Central London locations. Near London bridge and a second incident at Borough market a popular restaurant venue nearby. Police guns drawn telling people to get on the ground there are also reports of a stabbing the air with shots fired. And also a possible incident in South London near the box Seoul area that's a few miles from London Bridge. Police have confirmed that on Monday Ingrid a vehicles striking pedestrians. There are reports of injuries bodies on the ground the BBC reporting there's sought to their sources say more than one person has died. People are being told to leave and avoid the area. Police are also asking radio stations to broadcast of people caught up in this chaos to Brian. Two high. And to tell police if they see anything unto ward. It is a frantic and chaotic scene eerily reminiscent of the Westminster bridge attacked a few months ago which killed five people. The terror threat here is severe meaning an attack is likely. Com. He ought to confronting situation tonight we do want to mention are news partners at the BBC. Are confirming that at least two people have already died ABC news has yet to confirm this but our news porters at the BBC are reporting that we also have some eyewitnesses. Who were on the scene who saw some of what happened tonight let's listen that sound. But. Prohibits the shaving this shops. You can find him back back back but we've just been not been touched by Lebanese based in there are people of the black out. Everything looked so all the so I didn't see anything with my it bought. My friends. 03. Three. Way to keep the heat pregnant marine so. I think sleek cool people lying on the ground. And then it could be somebody an ambulance life. Back here at home we do know that the NYPD has been monitoring all the situations. That is happening there in London and the president re tweeting tonight a news report. From the Drudge Report that says fears of a new terror attack after van mows down twenty people on London Bridge so what do bring in our senior justice correspondent Pierre Thomas here we have seen. At least a dozen incidents in the last two years happened in European cities all across that continent. What you're seeing tonight give me your take. We'll have come we've talked to a number of federal law enforcement sources and as he said the president has been breached the National Security Council and monitoring the situation. At other relevant components of the FBI and Homeland Security. Right now the situation they don't know what that is exactly the suspicion is that it is terrorism against suspicion is that they don't know for certain. This notion of people using vehicle that low tech. Method of terrorism is a huge. Our ongoing issue Lockport than militant in the country have been going up. Almost monthly warning officials here that this is the mode of attack that that parents prefer at the moment again they're trying to get additional information. One source that we are getting out of the way they live rich do their work. Until they can determine what is going on in what it described as a danger. An ongoing situation. If these three incidents are all connected this this would look to be a larger terror plot and and slightly different. Then some of the lone wolf attacks we've seen recently in Europe. Well again we don't know all the details yet but clearly the brits are disturbed. And they believe perhaps that they have a cell of people that have been operating in that country are believed the latest report today that at least 500 people that were under. Surveillance at any different. Time in Great Britain so that the talks are ongoing situation again we don't know precisely what the finish yet but suspicion is that if it's probably going to be terrorism and law enforcement officials are to crowding situation we're in Great Britain they have scored in court the mostly young man. Could be potential radical. Pierre Thomas for us tonight we think Pierre Jennifer for their reporting and will continue to monitor these situations throughout the night again three separate emergency incidents happening in London tonight it is believed possibly. Possibly a terror incident but is still very early in the night so far for the latest developments check out abcnews.com. And of course on Good Morning America tomorrow on Tommy Thompson New York we thank you for watching we now return or scheduled program. This has been a special from BP's.

This transcript has been automatically generated and may not be 100% accurate.