Egypt has rearrested Mohammed al-Zawahiri, brother of Al-Qaeda number two Ayman al-Zawahiri, just days after he was freed under an amnesty for political prisoners, security officials said on Sunday.

The officials were not immediately able to give a reason for his detention overnight.

Mohammed al-Zawahiri was freed on Thursday, one of dozens of political prisoners who have been released by the Supreme Council of the Armed Forces since it took over when veteran president Hosni Mubarak was forced from office on February 11 by a wave of mass protests.

He had been in jail since 1999 when he was transferred into Egyptian custody by the United Arab Emirates after his arrest there.

An Egyptian court handed down a death sentence against him in his absence in 1998 on charges of undergoing military training in Albania and "planning military operations" in Egypt.