At least six explosions were heard near government buildings in Aden on Thursday.
Aden serves as a stronghold for the internationally recognized government after the Iran-backed Houthi movement seized the capital, Sanaa. The al-Maashiq Presidential Palace is the headquarters of the Yemeni government.
The city on the Gulf of Aden has been partly spared as fighting has escalated in Yemen and Saudi Arabia amid the ongoing regional war. Extensive attacks have targeted, among other places, the Saudi capital, Riyadh, and its international airport.
The Saudi-led military coalition has, in turn, repeatedly attacked Houthi targets in Yemen.
The Houthi movement says it also attacked a military headquarters in Aden.