By Ian McWilliam BBC correspondent in Kabul

Afghanistan's national airline, Ariana, has resumed flights between the Afghan capital, Kabul and Islamabad, the capital of neighbouring Pakistan.

Diplomatic relations between Islamabad and the interim government in Kabul had been wary, at best

Sunday morning saw the first general passenger flight between the two countries since Ariana stopped flying to Pakistan under the Taleban.

The Pakistani airline, PIA, is also due to begin flights between the two capitals shortly.

The resumption of flights will re-establish an important link between the two neighbours and is another indication that Afghanistan is rebuilding its ties with the outside world after years of isolation.

Commercial ties

Diplomatic relations between Islamabad and the interim government in Kabul had been wary, at best.

But some two million Afghan refugees still live in Pakistan and there are significant trade and business ties between the two countries.

The head of Ariana Airlines, Jahed Azimi, says he also expects business from foreigners working for the many international organisations which have been moving into Kabul. The flight will cost $200 for a one-way ticket.

Ariana Airlines has been coming to life since the lifting of United Nations sanctions which had banned all international flights from Afghanistan in the last years of the Taleban.

The sanctions were removed in February after the Taleban's collapse.

New planes

Not long ago, Ariana was down to only one working aeroplane, but with the recent purchase of a Boeing 727 from American Airlines, it has doubled its fleet.

India's announcement that it is to give the Afghan airline three European Airbuses will be another major boost.

Internationally, Ariana already flies to Delhi and the United Arab Emirates.

It has only one domestic route to the western city of Herat, but Captain Azimi says he hopes Ariana planes will link all of Afghanistan's main cities once the regional airports are upgraded and when the routes are considered commercially viable.