Pakistan-US relations have been strained since Osama bin Laden was killed in a unilateral US incursion into Pakistani territory. These tensions have cast a shadow over further cooperation in security matters, including the questioning of bin Laden's wives.

Osama Bin Laden is dead, but for the US, the fight against al-Qaeda goes on.

Washington is hoping to question bin Laden's wives in order to gain more information about al-Qaeda.

But to do this, it needs cooperation from Pakistan. Bin Laden's three wives and several of his children have been detained by Pakistani forces since the US raid last week. The United States believes that they are now the key to tracing bin Laden's previous movements and the activities of his global network.

However, Pakistan has so far not granted the US access.

Pakistanis are angry about the unilateral US action, despite Washington's insistence that the operation was legal. A British newspaper reported that Washington and Islamabad reached a secret deal in 2001 to allow US special forces to kill or capture bin Laden inside Pakistan. However, former Pakistani President Pervez Musharraf denies that his administration struck such a deal with the US during his tenure.

While tensions have flared up between the US and Pakistan, Al Qaeda based in Yemen have warned that bin Laden's death does not signal the end of the fight. The group has threatened to carry out further attacks in the future.

It has also been reported that bin Laden's youngest son, Hamza, escaped the US assault on his father's secret compound. Hamza, dubbed the "Crown Prince of Terror", was bin Laden's closest confidante and many believed him to be a potential successor. Spy chiefs fear his escape may allow the bin Laden legacy of terror to live on.