A police officer is now said to be in a serious but stable condition after being hit by a lorry during an anti-smuggling operation in south Armagh.
Police on both sides of the Irish border are searching for the driver of a lorry which struck two PSNI officers during a customs raid on Tuesday.
The two officers were hit as they took part in a search of a warehouse on the Low Road, near Meigh at about 1300 BST.
The second officer's injuries are not thought to be life threatening.
Seven million cigarettes were recovered. Two men have been arrested.
The seriously injured policeman was airlifted from the scene by helicopter. He was taken to the Daisy Hill Hospital in Newry and later transferred to the Royal Victoria Hospital in Belfast.
The officer suffered very serious injuries to his upper body and has undergone emergency surgery.
It is understood that over the weekend a cargo of smuggled cigarettes arrived from China in Dublin Port.
It is believed it was then watched by customs officers in the Irish Republic as it was brought to Dundalk.
Earlier on Tuesday, the container was taken across the border to warehouses near Meigh.
It is understood a number of armed PSNI officers and revenue officials raided the warehouse as the cigarettes were being unloaded.
The driver of one lorry drove through a roller door as he escaped and hit the two PSNI officers, who were outside.
The lorry drove the short distance to the border at high speed.
However, as the driver was turning the truck into a yard in the Irish Republic, he lost control.
The lorry ended up on its side and a search is now underway on both sides of the border for the driver.
PSNI Inspector David Beck condemned those responsible.
"These officers were doing their utmost to prevent and tackle crime in the south Armagh area," he said.
"But unfortunately those involved were prepared to risk the lives of these officers. Their actions are in sharp contrast to the actions of the officers."
Sinn Fein MP for the area Conor Murphy said he condemned the incident and that his thoughts were with the injured officer.
DUP MLA William Irwin said it was a "dastardly crime".
"Our thoughts and prayers go out to the officers and their families," he added.