A bomb exploded next to the governor's office in Yemen’s southern city of Aden and killed four people on Thursday, according to the officials.
The governor Nayef al Bakri who was appointed governor by the exiled President Abd Rabu Mansour Hadi last month was also present in the office, but he was unharmed.
Aden has been the temporary seat of Yemen's administration for a while as the Houthi group holds the capital city, Sanaa.
This is the first attack since pro-government forces recaptured the city from the Iranian-backed Houthi rebels.
No one claimed responsibility over the bombing in Aden yet, however, ISIS militants undertook another deadly attack on a Yemeni military post near the Saudi border.
A local official reported that unknown gunmen attacked the government military post in the Thamud district near Saudi Arabia, killing four soldiers.
ISIS has claimed responsibility in an online statement that they carried out the assault on the "apostate army."
The attacks underline the fragility of Yemen's government in spite of assitance of hundreds of air strikes from the Gulf Arab states.
The government has won control over most of the country and reversed the gains of the Houthis, an Iran-backed militia with the capture of Aden, following a five-month long civil war that killed over 4,300 people.
However, until a political accord is provided, suffering and hunger continue to spread in the country.
Twenty million people in the country are in need of aid, 13 million are facing food shortages and 9.4 million are having difficulties accessing drinking water.