Susannah Price BBC Correspondent in Islamabad

The commander of the American campaign in Afghanistan, General Tommy Franks, has arrived in Pakistan to watch the first joint military exercises between the two countries in four years.

His visit comes a month after senior defence officials met in Pakistan to discuss restoring military ties.

This new cooperation clearly stems from Pakistan's help in the war on terror.

US-Pakistan relations improved after September 11

The two week exercise involves more than 100 American army personnel.

They are the first joint exercises involving American and Pakistani troops since Washington suspended military ties with Islamabad.

The US imposed sanctions against Pakistan for its nuclear tests in 1998.

Improved relations

But the sanctions were lifted after Pakistan pledged its full cooperation to the American war on terror.

Last month the US Under Secretary of Defence came to Pakistan to participate in the first formal meeting of the revived defence consultative group.

The restoration of ties is linked to Pakistan's cooperation with American operations in neighbouring Afghanistan and in hunting down al-Qaeda fighters inside Pakistan.

Religious parties fared well in Pakistan's elections

However the American government will be concerned about the unprecedented success of an alliance of Islamic parties in last week's general election.

The alliance, which won the third largest number of seats, has stated its opposition to America's use of bases inside Pakistan and to what it terms 'foreign interference'.

It's not yet known whether the religious parties will make up part of the new government, but they could well have an influence on future foreign policy.