Image caption Mr Coleman says his daughter needs medical care

The family of a pregnant American woman missing with her husband in Afghanistan have made a fresh appeal for her safe return.

Caitlan Coleman, 27, is due to give birth in January and needs urgent medical attention, her father told the Associated Press news agency.

James Coleman said she had been travelling with her Canadian husband across Central Asia.

There are fears they were abducted, but no ransom has been demanded.

No militant group has said it is holding the couple and AP says when it contacted the Taliban two months ago, a spokesman said no Taliban members were involved.

The couple last contacted their family on 8 October from what Mr Coleman described as an "unsafe" part of Afghanistan.

It is not clear how they entered Afghanistan and what exactly they were doing there - they had also travelled through Kazakhstan, Tajikistan and Kyrgyzstan.

Mr Coleman adds that his daughter needs medical care for a liver ailment.

"Our goal is to get them back safely and healthy," the father told AP. "I don't know what kind of care they're getting or not getting...we're just an average family and we don't have connections with anybody and we don't have a lot of money."

One Afghan official contacted by AP says the trail has gone cold, after initially suggesting that they may have been abducted in Wardak province in an area about 25 miles (40km) west of the capital Kabul.

But there has been no independent confirmation of this - at the time the couple went missing officials in Wardak told BBC Afghan that they had no information about them.

The US State Department and Canadian Foreign Affairs Ministry say they are looking into the disappearance, AP says.

Correspondents say that the kidnapping of foreigners has become relatively common in parts of Afghanistan since the US-led invasion of the country in 2001.

Earlier this month an American doctor who had been abducted by the Taliban in eastern Afghanistan was rescued.

Dilip Joseph, of the Morning Star Development aid group, was freed by US and Afghan forces in a joint operation that killed seven of his captors.