LASHKAR GAH, Afghanistan, Oct 20 (Reuters) - Six Afghan policemen were killed in Helmand province in a so-called "insider" attack involving a rogue Afghan policeman and a chef, local officials said on Saturday.
The Taliban took responsibility for the attack, saying they had despatched a "mujahid who had infiltrated and penetrated the police ranks", spokesman Qari Yousuf Ahmadi said.
The policeman and chef working for the officers approached a police checkpoint in Helmand's Grishk district on Friday where they opened fire and shot dead two of their colleagues, the provincial governor's office said in a statement.
Insurgents then rushed to the scene, and killed four more policemen, the statement said.
Police officials added that the chef previously attempted to kill the officers by poisoning their food.
"First the cook poisoned his comrades and then he joined the Taliban and decided to shoot them instead," said Farid Ahmad Farhang, a Helmand police spokesman.
At least 52 members of the NATO-led force have been killed so far this year in insider attacks, prompting NATO soldiers to be armed at all times and leading the Afghan security services to introduce stricter vetting procedures.
The majority of those attacks are not Taliban-related, NATO and U.S. officials have said, but stem rather from personal grievances.
Separately, two officials in Helmand's Sangin district were ambushed and killed by insurgents as they drove car to a tribal elders' meeting, the province governor's office said. (Reporting by Abdul Malik and Mirwais Harooni; Writing by Amie Ferris-Rotman; Editing by Nick Macfie)