Seven people were killed Sunday in a suicide bomb attack targetting the head of security in Yemeni President Abd Rabu Mansour Hadi's temporary capital of Aden, eye witnesses said.
Aden security chief Shalal Ali Shayea was not injured in the attack on his house, local newspaper Aden al-Ghad reported, quoting sources close to Shayea.
Two of the security chief's guards and five passers-by were killed in the attack, carried out by a bomber in an explosive-rigged car, eye witnesses told dpa.
Local fighters backed by Gulf troops cleared the mainly Shiite Houthi rebels, who control the capital Sana'a, from Aden in July.
Hadi and his Saudi-backed government later returned to the city from exile in Riyadh but have been unable to prevent a series of assassinations by Islamic State jihadists, who last month claimed responsibility for a car bomb attack that killed the provincial governor.
Rival jihadists from al-Qaeda are also reported to be present in the city, and they openly control a large region of south-eastern Yemen behind government lines.
Amid ongoing fighting between the mainly Shiite Houthis and their opponents, two other senior security officials were also killed on Sunday.
A general loyal to Hadi was killed by a bomb planted in his car in the flashpoint central province of al-Baida, where the Houthis are battling local fighters and al-Qaeda jihadists.
In Sana'a, unidentified gunmen shot dead Mohammad Radman, a senior official in the elite Special Security Forces, loyal to the Houthis.
There were no immediate claims of responsibility for any of the attacks, although the Aden bombing bore the hallmarks of Islamic State.
The jihadist organization has built up a presence in the Arabian Peninsula country during the devastating ten-month war between the Iran-aligned Houthis and a range of local forces backed by Gulf troops and Saudi-led airstrikes.
Saudi Arabia fears that the rebels will give Shiite Iran, their regional arch-rival, a strategic foothold in the Arabian Peninsula.
Despite intensive air raids, the Saudi-led campaign has made little progress since the recapture of Aden, with the Houthis still claiming repeated raids on Saudi border positions.