The weapons were stored in Bashgah, a village in Baghlan province 75 miles north of Kabul, Interior Ministry spokesman Latfullah Mashal said. The cause of the blast was not known.

"It's damaged the whole village, including the mosque and six houses," Mashal said.

He said the wounded had been rushed to hospitals and forecast that the death toll would rise.

Mashal said the cache had been hidden in an underground bunker close to the house of a former militia commander to shield them from a U.N.-sponsored disarmament drive.

Baghlan police chief Gen. Fazeluddin Ayar said the cache dated from "a long time ago" but had no further details. The country is awash with old weapons, many of them stored during the resistance against occupying Soviet forces during the 1980s.

Earlier suspected Islamic militants beat to death a mother and her two daughters in northern Afghanistan because they worked for a foreign reconstruction group, officials and a western security source said yesterday.

The three women were employed at the Bangladesh Rural Advance-ment Committee, a microcredit organisation, in the northern province of Baghlan, the security source told AFP on condition of anonymity.

Their bodies were found Sunday with a letter attributed to a wing of the radical Hezb-e-Islami organisation, the source added. The group is led by former premier Gulbuddin Hekmatyar, who is on the US most wanted terror list.

"The letter said they had been murdered as retribution for working for non-governmental organisations and for their whoredom," the source said.

Provincial police chief Fazelud-ing Ayar confirmed that the bodies of three women were found Sunday night and that they had been beaten to death.

"We have arrested four men who are suspects in this brutal act. The investigation is ongoing," he told AFP.

The police chief named two of the victims as Mehboba and Bibi Shirin and said the third has yet to be identified.

The western security source said: "It was a mother and two daughters who all worked for Bangladesh Rural Advancement Committee."

Afghan interior ministry spokesman Lutfullah Mashal also confirmed the murders but could not say if the women were killed for working with foreign aid groups.

"I can confirm that three women were found murdered in Baghalan province but it is yet to be known who killed them and why," Mashal said.

Afghan officials said last week that 17 Hezb-e-Islami militants had laid down their arms and surrendered to authorities in the southeast of the country.

However, it was unclear if any members of the fundamentalist anti-US organisation would be eligible for a government amnesty offered to the ousted Islamic Taliban.

Northern Afghanistan is generally much safer and secure than the Taliban-infested south and southeast of the country.