Gardaí have arrested three people after a car they had been pursuing crashed into another vehicle on the N7 in Co Kildare this afternoon.
One person has been seriously injured.
The road is closed northbound between Junction 7 and Junction 8, and there are major tailbacks.
The Garda Síochána Ombudsman Commission is also investigating the incident.
It is believed that armed detectives in an unmarked garda car had been patrolling the N7.
They signalled for a car to stop. When they approached the stopped car, the car sped off.
A short time later, the car was involved in a collision with another car.
Three of the four people in the car gardaí were interested in have been arrested. They are two young men and a young woman in their teens.
A fourth person, another young man, was seriously injured and taken to hospital.
The occupants of the third car are believed to have been uninjured.
Emergency services remain at the scene and a section of the motorway remains sealed off. Motorists are urged to avoid the area.
Gardaí in the unmarked vehicle were patrolling as part of Operation Thor, which targets rural burglaries
I am thankful the people in the other car are not hurt this first and foremost.
The Garda have done their job which I am sure is quite a difficult one when they get it right they need to be praised.
The people in the car who caused the crash are 100% to blame I am not happy one of them is in a serious condition however I have zero sympathy for them either as they had zero regard for other road users.
3 arrested people in the other car thankfully unhurt bravo Gardaí.