The leader of Al Qaeda, Ayman al-Zawahiri, says his network "will spare no effort" to free prisoners being held at the US Army detention centre at Guantanamo Bay, Cuba.

Zawahiri, who has been the subject of a $25 million bounty since the 9/11 attacks, said: "We pledge to God that we will spare no effort to free all our prisoners, on top of whom are Omar Abdel Rahman, Aafia Siddiqui, Khaled Sheikh Mohammed and every oppressed Muslim everywhere ...,"

Pledge follows recent jailbreaks

Zawahiri's pledge comes after a number of recent jail breaks in Iraq, Libya and Pakistan. Close to 2,000 militants have been freed in the raids, which have all come in the past two weeks.

Al Qaeda has claimed responsibility for the raids in Iraq and Libya, while the Taliban says it was behind the strike on a jail in Pakistan.

Zawahiri did not elaborate on any specific plan to attack Guantanamo Bay, where over 150 suspected militants are being held by the US military.