Six people were killed, two of them police officers, when an articulated lorry accidentally ploughed into a police checkpoint in southern Spain early on Tuesday, the regional government said.

Three other Guardia Civil police were also hurt in the incident which took place around 4:30 am (0330 GMT) on a highway south of Seville, police said.

The checkpoint had been set up as part of a routine police operation to prevent drug trafficking, the AEGC Guardia Civil union said.

Following the accident, the driver was arrested, but media reports said he had tested negative for alcohol and drugs.

Rafael Jimenez Onetti, head of the area's police traffic unit, said four civilians and two police officers died in "a road accident" involving "an articulated lorry carrying vegetables, three private vehicles and four police cars".

"It was not intentional.. (the lorry) reached the marked checkpoint and crashed into the cars that had stopped there including the police vehicles," he told reporters.

Speaking to public television, Pedro Carmona, who belongs to another union, the AUGC, said the driver had "lost control" of the lorry and "steamrolled into the vehicles that were waiting at the checkpoint".

He said there was a second driver in the lorry who was sleeping at the time.

Francisco Toscano, a central government official based in Seville, told Cadena Ser radio the driver appeared to have been "distracted".

The deadly accident prompted a string of condolences on X, with Andalusian regional leader Juan Manuel Moreno "greatly saddened" by the news and Prime Minister Pedro Sanchez sending his "love and support" to the victims' families and the wounded.

On February 9, another two Guardia Civil police were killed in Andalusia when they were rammed by a drug traffickers' boat during a chase in Barbate harbour near the southern port of Cadiz.

Spain is one of the main entry points for drugs into Europe given its close ties with Latin America, which is the main source of cocaine, and its proximity to Morocco, which is a key source of cannabis resin.