(Reuters) - Yemeni President Ali Abdullah Saleh, a key U.S. ally against al Qaeda, said on Wednesday he will not seek to extend his presidency in a move that would end his three-decade rule when his current term expires in 2013.

Eyeing protests that swept Tunisia's leader from power and threaten to topple Egypt's president, Saleh also vowed not to pass on the reins of government to his son. He also appealed to the opposition to call off protests as a large rally loomed.