Seventeen soldiers have been killed in an explosion at a military base near Iran's capital Tehran, officials say.

伊朗官员称，首都德黑兰附近一座军事基地发生爆炸，17名士兵被杀。

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A local resident said the sound of the blast was 'deafening'

The blast occurred when weapons were being moved inside a Revolutionary Guards depot², a spokesman for the elite³ unit told state TV.

Windows in nearby buildings were shattered and the blast was heard in central Tehran, 40 km (25 miles) away.

Two hours after the explosion a fire still raged（发怒，狂暴） and there were traffic jams on nearby roads, a local reporter said.

The death toll⁴ was revised down from an earlier figure released by the Revolutionary Guards of 27.

Local MP Hossein Garousi said "a large part of an ammunition⁵（弹药） depot exploded," parliament's website reported.

Revolutionary Guards spokesman Ramezan Sharif did not say what had caused the "accident" in the village of Bidganeh, near the city of Karaj.

"Some of the casualties are reported to be in a critical condition," he said.

An emergency worker said that 12 people had been taken to hospital.

Karaj resident Kaveer told the BBC's Newshour programme that the sound was "deafening".

"We were kind of shocked. I just ran out of the house and looked around," he said.