The local authorities in Yemen's temporary capital, the southern port city of Aden, has tightened security measures after a car bomb killed governor on Sunday.
ISIL claimed responsibility for the bombing which killed governor Jafar Saad and his 6 bodyguards.
Officials said president Abd Rabbuh Mansour Hadi is overseeing the security measures and has asked the Saudi-led coalition to provide further support to restore stability in the city.
The coalition has deployed thousands of Arab troops to help the government of Yemen secure Aden.
Hours after ramming an explosives-laden car into the convoy of the governor, gunmen shot dead a security officer in the city, the officials said.
The incidents occurred a day after gunmen shot dead a judge and a security chief.
Since it was retaken from the Houthi militants with help from the Arab coalition, Aden has been experience huge challenges including a series of targeted killings of officials.
Other challenges include spread of weapons in civilian hands and growing presence of militant groups such as Qaeda and ISIL.
On Saturday, UN envoy to Yemen Ismail Ould Cheikh paid a short visit to Aden and met with Hadi.
The meeting discussed preparations for a new round of talks between the government and the Houthi militants.
Officials in Aden said the talks are scheduled to start in mid December in Geneva.