we can speak to robert nesbitt who has been reporting from the scene are close by for the last hour. >> i'm joined now by someone who is on westminster bridge at the time this incident happened. take us through what you saw. >> i was walking across the bridge when suddenly a bus stopped in front of me and every started screaming. i saw a trainer in the road, issue, unfortunately, someone was hit by a car. a body was on the other side of the road. and then another body for the route. we looked at the other side, there is another body lying in the water. >> any indication at what causes people to be entered? i do see a car come through? >> i didn't see anything. the first thing i was aware of was people starting to scream and people coming off the bus looking very shocked. there is a lot of confusion and people who started dealing with the casualties. at that point, i tried to stop people from coming onto the bridge because a lot of people were coming on. >> how did you do that? >> just trying to waive them back. i think people could tell because people were screaming that some thing t