ADEN (Reuters) - A suicide bomber blew himself up in front of a Yemeni election committee office in the southern port city of Aden early on Tuesday, a security official said, one week before an election to replace outgoing President Ali Abdullah Saleh.
The official said the unidentified bomber was wearing an explosive belt that detonated before he reached the election committee building in the Crater district of Aden, killing him instantly but injuring no one.
The attack was the latest sign of opposition to the February 21 vote, rejected by southern separatists, northern Shi'ite rebels and Islamist militants emboldened by political upheaval that has weakened central government control over swathes of Yemen.
Last month, unidentified gunmen attacked another election committee office in the southern province of Dalea.
Security reinforcements are now being sent to all election committee offices in Aden, the official said.
Saudi Arabia and the United States are pinning their hopes on the vote as a step towards ending instability, which they fear is giving al Qaeda's Yemen-based wing room to expand its foothold near oil shipping routes through the Red Sea.
One soldier and two Islamist fighters were killed in overnight clashes in the southern city of Zinjibar, parts of which are still controlled by militants, a local official said.
A spokesman for Islamist group Ansar al-Sharia (Partisans of Islamic Law), which has seized several towns in south Yemen, said in a text message that the militants had shot dead two soldiers.
Saleh is in the United States receiving medical treatment for injuries inflicted during an assassination attempt but has said he will return home before the vote, casting doubt on his commitment to leave office in line with a Gulf-brokered plan to end a year of political upheaval.
Reporting by Mohammed Mukhashaf; Writing by Isabel Coles; Editing by Tim Pearce