A heavy dust storm hit Iran's capital Tehran, blacking out the sun in a swirling cloud and tearing down trees in a squall that reportedly killed at least four people and injured at least 30.

The storm struck Tehran on Monday with winds of up to 110km per hour, state television reported. The report said the storm killed five people, while Iran's official IRNA news agency said it killed four people as winds hit 130km per hour. 

The storm broke trees and plunged the capital into darkness for several minutes.

It also caused a chain-reaction crash involving 20 vehicles on a highway south of the capital and international flights were cancelled, according to the TV report.

Air traffic controllers diverted several domestic flights to central Iran.

Authorities asked children and the elderly, as well as those with heart problems, to remain indoors due to the dust. The TV report said heavy winds also engulfed parts of central Iran, but no casualties were reported there.

Source: AP