Farah province early Wednesday, killing all 25 people on board.
Naser Mehdi, a spokesman for the provincial governor, says the chopper crashed around 9:10 am. Anar Dara district and heading for nearby Herat province.
He said the passengers included the deputy corps commander of Afghanistan's western zone and the head of the farah provincial council.
Mehdi said the helicopter went down in bad weather, but the Reuters news reports the Taliban claims it shot the aircraft out of the sky.
Reuters says the doomed helicopter was one of two army choppers flying to Herat.
Separately, to Afghan Interior Ministry official said a suicide bomber struck outside the country's largest prison early Wednesday, on the eastern edge of the capital Kabul, killing seven people including prison workers and security personnel.
Najib said the attacker targeted a bus carrying prison workers. The sprawling Pul-e-Charkhi prisoners hundreds of inmates, including scores of Taliban.
According to Abadullah Karimi, a prison official, who was arrested and was arrested.
No one took immediate responsibility for the attack.
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