Mr Silanyo, an ageing scion of the Somali National Movement, which fought the Barre regime, lost the 2003 vote to Mr Kahin by 80 votes amid suspicions of electoral fraud.
However, early indications were that Mr Kahin, who became president in 2002 when his predecessor died and who once served in the regime of Siad Barre, Somalia's last military dictator, had lost to Ahmed Silanyo.