Seven police officers were taken to hospital after being injured in a horrific collision during a pursuit on the A1 in Tyneside early on Wednesday morning.
Northumbria Police confirmed that two people have been arrested over the incident, which shut the motorway.
As well as long delays on the dual carriageway, at least four marked police vehicles were wrecked.
The North East Ambulance Service said it took a number of patients to hospital following the early morning smash.
Images from the scene near Denton, Newcastle, also show a car on its side and debris scattered across the northbound carriageway.
One of the police vehicles had its roof torn off.
A black BMW also appears to be damaged in the incident.
Crash investigators have been sent to the scene of the pile-up, which happened at around 2.30am on Wednesday.
Newcastle Airport warned anyone going on a flight to allow “additional time”.
National Highways said the A1 will be closed between Swalwell in Gateshead and Denton in both directions into Wednesday afternoon.
It said: “A multi-vehicle collision resulting in serious injuries occurred at approximately 0230 this morning (Wednesday 9th April).
“Due to the severity of the collision a full Northumbria Police investigation is under way and they advise that it will be protracted.
“The road is expected to remain closed in both directions into the afternoon of Wednesday 9th April.”
A Northumbria Police spokesman said: “Shortly before 2.30am today (Wednesday) we received a report of a multi-vehicle collision on the A1 northbound near the Derwenthaugh Road junction, Gateshead.
“Emergency services are currently in attendance.
“A section of the road is closed in both directions – there are diversions in place from the Derwenthaugh Road junction northbound, and the A69 roundabout southbound.
“Motorists should use alternative routes where possible.”
A North East Ambulance Service spokesperson said: “We received a call at 2.29am on Wednesday April 9 to reports of a road traffic collision on the A1 northbound near Denton, Newcastle.
“We dispatched five ambulance crews, a specialist paramedic, a duty officer, two crews from our hazardous area response team (Hart) and requested support from our colleagues at the Great North Air Ambulance Service (GNAAS) who attended by road.
“Five patients were transported to hospital for further treatment.”
