BAGHDAD — Al-Qaida's leader says a prisoners' hunger strike in Guantanamo Bay has revealed the "odious" face of America and claims that the terror network will spare no effort to free prisoners held at the US military-run detention center in Cuba.

Ayman Al-Zawahri spoke in a 22-minute audio message posted on the Internet on Wednesday.

"The strike by our brothers in Guantanamo reveals the real odious and ugly face of America. We pledge God that we will spare no efforts to set them free," he said

Some of the 166 prisoners at Guantanamo began a hunger strike earlier this year to protest conditions and their indefinite confinement.

The message's authenticity could not be independently confirmed but the message was posted on a militant website commonly used by al-Qaida.