A charter jet carrying US citizens between Afghanistan's Bagram airbase and Dubai was forced to land in Iran due to "bureacratic issues", a US official has said.

The state department offical was reported on Friday as saying that the plane changed its course and landed in Bandar Abbas because of a bureacracy and "issues with the flight plan".

"Contrary to press reports, this plane was not forced down by the Iranian military," the official told the AFP news agency.

The official said the Iranian authorities asked the Fly Dubai aircraft, designated FZ 4359, to return to Afghanistan.

When told the aircraft did not have enough fuel to fly back, it was rerouted to Bandar Abbas, the Reuters news agency reported. It was later allowed to take off and fly to Dubai.

The plane was carrying about 100 US citizens, the official said.

Fly Dubai also played down the incident, saying in a statement that the flight "has been diverted en route to Dubai and an updated arrival time is being established.

Iran and the US enjoy a fractured relationship, at odds over the former's nuclear programme, but cooperating in Iraq against fighters from the Islamic State group.

Source: Agencies