Gunmen fired an RPG on a car that was parked at the bureau of the Islah Party in Yemen's temporary the capital the southern port city of Aden on Tuesday night, a local official said.
A manhunt was launched for the attackers who ran away after the incident, the official said, adding a passerby was seriously injured from explosion.
The incident came shortly after gunmen besieged the national bank in Crater district.
Aden has been experiencing alarming security problems including presence of militant groups such as Al-Qaeda since it was retaken from the Houthi militants in mid this year.
Many security officers and other officials have been killed and blasts reported as the government is struggling to bring the situation under control.
The Saudi-led coalition, which has been bombing Yemen, has sent thousands of troops to heck the government restore security and stability in Aden.
On the other hand, Houthi media reported that the Houthi forces fired a new ballistic missile into Saudi Arabia.
In recent days, the Houthis fired several ballistic missiles against military and non-military targets in Saudi border towns within their escalated responses to ongoing Saudi-led airstrikes.
Though they said all missiles hit the targets precisely, the coalition said it had intercepted them.