KABUL, Afghanistan — Eleven U.S.-trained Afghan police officers defected to the Taliban on Monday in southern Helmand province, the spokesman for the province’s governor told McClatchy.

Daud Ahmadi, the spokesman, said the officers took their weapons and equipment with them – 11 AK-47 assault rifles, two heavy machine guns and three motorcycles.

The U.S. military has made a major effort to train local police officers, seeing the group as essential to fighting the Taliban and maintaining local security. But their loyalty to Afghan’s central government in Kabul has long been questioned as is their involvement in human rights abuses.

The Afghan policemen went over to the Taliban at 1 a.m. in the village of Deh Zoor in the Musa Qala district, Ahmadi said. Ahmadi said their defection would have no “negative impact on the duties and morale of our security forces.”

“The local police are fighting the Taliban in Helmand every day,” he said.

Abdul Wahab, a tribal elder from Musa Qala, told McClatchy that the police officers and the Taliban to whom they surrendered were members of the same tribe.

The Taliban confirmed the defection in a Twitter message.

Separately, a bomb tied to a donkey killed a district police chief in the central province of Ghor. According to the province’s deputy police chief, Gen. Sayed Hussain Safawi, the district police chief of Charsadda was on his way to work at about 8:30 a.m. when the bomb was detonated by remote control. In addition to the district police chief, three people, including the chief’s body guard, were wounded in the explosion.

Ghor is a mountainous province where the Taliban has long had a dominant presence. Safawi said the attack on the district police chief, Gul Ahmad, was intended as revenge for a recent government push against the Taliban.

Safawi said another local official, the district intelligence chief in Daulatyar, had been killed on Sunday when Taliban assassins ambushed him as he was riding his motorcycle to work.