The shooting broke out on Friday evening during festivities for the 13th anniversary of the fall of Afghanistan's last communist government.

City police chief Baba Jan said Afghan army soldiers helping with security opened fire in an apparent attempt to control a crowd.

However, Interior Ministry spokesman Latfullah Mashal said shots were fired during a row between troops and police.

A Reuters report backed Mashal's claim saying the clashes were between members of the US-trained Afghan army and police.

Jan said one woman died at the scene and another later in hospital. Others were injured in the ensuing panic. Revellers later mounted a stone-throwing protest against the security forces, Mashal and witnesses said.

"We have received the bodies of three military and three civilians who were killed in the clash," a doctor at Herat's main hospital told Reuters on Saturday.

Investigation

President Hamid Karzai expressed condolences to the victims. He ordered an investigation and "severe punishment" for those responsible, his office said in a statement.

Karzai ordered an investigation
into the Herat clashes

Officials said one soldier had been arrested over the incident and that a team of investigators was en route from Kabul.

Herat, near the border with Iran, was for years seen as one of the safest parts of Afghanistan, but serious violence has broken out twice there since early last year, including riots in September after the dismissal of the city's former governor, Ismail Khan.

The city was calm on Saturday morning, but UN staff and other aid workers had been ordered not to venture out, aid officials said.