A suicide car bombing killed four people Monday when it hit a gathering of loyalist forces in Yemen's Aden, the southern city serving as a government base, a security official said.
Five others were wounded in the attack in the residential Sheikh Othman district, the official said.
The suicide bomber rammed his explosives-laden vehicle into an area where security forces and pro-government militiamen had assembled, the official said.
President Abedrabbo Mansour Hadi has declared Aden as Yemen's temporary capital as Sanaa remains in the hands of the Iran-backed Huthi rebels and their allies since they seized it in September 2014.
Al-Qaeda and the Islamic State group have stepped up attacks in Aden despite the efforts of the government and its backers in a Saudi-led coalition battling the Huthis and their allies to secure it.
The rebels controlled Aden for months before government loyalists pushed them out in July.
Because of the unrest gripping Aden, Hadi himself and many senior government officials spend most of their time in Riyadh, which has led an anti-rebel coalition since March 26 last year.