At least two people have been killed in an explosion and fire at an Iranian oil refinery during a visit by the country's president, Mahmoud Ahmadinejad, according to state media reports.

The Mehr news agency said Ahmadinejad was unhurt by the explosion, which reports said was due to a gas leak.

"Currently the control of the fire and the rescue operation has been completed and the investigation of the blast has commenced," Mehr said.

The incident, according to the Fars news agency, also injured 22 people and occured at a refinery in Abadan, in the country's southwest on Tuesday.

Ahmadinejad was at the refinery to inaugurate a unit that will increase Iran's petrol production capacity by an extra 4.2 million litres a day.

State media also reported that Ahmadinejad ordered a special plane to airlift those injured to the capital, Tehran.

'Black smoke'

A local resident in Abadan told the Associated Press news agency that he saw ambulances and rescue teams rush to the site shortly after the explosion.

He also said that residents had noticed black smoke coming from the refinery in the past few days, which he speculated could have been from a fire.

During his speech shown on state television from Abadan, Ahmadinejad appeared unperturbed, telling local officials that Iran was today able to meet all its domestic oil needs.

Iran has launched expansion projects at refineries to stave off damage from sanctions, imposed by the West on fuel sales to Iran over the country's controversial nuclear programme.

Western powers suspect Iran is pursuing nuclear arms, a charge the government has denied. It says its nuclear programme is aimed for peaceful energy production.