ISLAMABAD (Reuters) - Al Qaeda chief Ayman al-Zawahiri has appeared in an audio interview calling on fighters to take Western hostages and exchange them for jailed jihadists, the monitoring service SITE Intelligence Group said on Sunday.

In recording posted online, Al-Zawahiri called on the global militant network to kidnap Westerners "until they liberate the last Muslim male prisoner and last Muslim female prisoner in the prisons of the Crusaders, apostates, and enemies of Islam," according to SITE.

Reuters could not verify the authenticity of the recording. Zawahiri is believed to be seeking refuge in the Afghanistan-Pakistan border area that is the Taliban's base.

(Writing by Mehreen Zahra-Malik; Editing by Raissa Kasolowsky)