Twelve people including four policemen were killed on Saturday in an attack by Al-Qaeda-linked militants on a checkpoint in Yemen's southern port city of Aden, police said.

"Armed men from Al-Qaeda attacked a security forces checkpoint at Jawala at the northern entrance to Aden, killing four police officers," a police source told AFP.

The source, updating an earlier toll, said eight assailants were killed as security forces responded.

The attack comes after at least 222 people including 183 militants were killed in five days of clashes this week around the strategic southern town of Loder which Al-Qaeda is trying to seize, according to local sources.