Paramedics have treated a man for serious injuries following a crash in Frostenden.
Emergency services – including firefighters and police officers – are at the scene of the accident in Gipsy Lane.
A police spokesman said a man, who is believed to have been driving one of the cars, has been taken to hospital.
His injuries are described as serious, but not life-threatening or life-changing.
Firefighters from Southwold, Halesworth and Lowestoft South were sent to help at the scene at 6.11pm.
They had called a stop to the incident at 7.27pm.
No-one else involved in the crash is believed to have been hurt, the police spokesman said.
One lane of the A12 southbound is currently blocked between the road’s junctions for Frostenden and Clay Common.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here