Pakistan's Taliban have threatened in a video message to use suicide bombers and snipers to kill former President Pervez Musharraf when he returns home from exile.
Mr Musharraf angered the Taliban and other groups by joining the United States in its so-called war on terror following the 11 September 2001 attacks.
He later launched a major crackdown on militancy in Pakistan, Reuters reports.
Mr Musharraf is due to return home from Dubai on Sunday, after nearly four years of self-imposed exile, in time to take part in May's parliamentary elections.
Pervez Musharraf seized power in a 1999 coup and resigned in 2008 when his allies lost a vote and a new government threatened him with impeachment. He left the country a year later.
The former army general faces the possibility of arrest on charges that he failed to provide adequate security for former prime minister Benazir Bhutto before her assassination in 2007, and in relation to other cases.