An Afghan official says an army helicopter carrying senior officials crashed in the western 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 a.m. shortly after taking off from the mountainous Anar Dara district and heading for nearby Herat province.

On board were the corps commander, Gen. Naimudullah Khalil, and two members of the Farah provincial council: its chairman, Farid Bakhtawar, and Jamila Amini, one of only two women on the nine-member council.

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Wednesday's was the second army helicopter crash in as many months in Farah. In September, five crew members died when their helicopter crashed. Investigators blamed the crash on a technical failure, without elaborating.

Mehdi said the doomed helicopter went down in bad weather, but the Reuters news agency 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, an 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 Danish said the attacker targeted a bus carrying prison workers. The sprawling Pul-e-Charkhi prison houses hundreds of inmates, including scores of Taliban.

According to Abadullah Karimi, a prison official, the attack occurred near the prison gate, where a number of visitors were waiting to pass a rigorous security check before entering. No one took immediate responsibility.