Police colonel and others killed by gunmen in Aden attacks

Unidentified gunmen on Sunday killed a police officer and four others in Yemen's Aden in a wave of attacks targeting security forces in the violence-plagued port city.

Assailants on Sunday opened fire on a police vehicle carrying Colonel Taha al-Sobeihi in Aden's Mansura district, killing him along with a bodyguard and a female bystander, a security official said.

Al-Qaeda and the rival Islamic State (IS) group both have a presence in the city, where they have occupied government buildings and are seen patrolling several districts and intimidating civilians.

They have claimed a string of attacks in recent months. 

Late on Saturday, unidentified gunmen killed a soldier in Mansura, a security official said. 

The man was a recruit in a new force that is loyal to President Abd Rabbuh Mansour Hadi and trained by the Saudi-led coalition, which in March launched a military campaign against rebels who had overrun large swathes of the country.

Hadi last year named Aden as his government's temporary capital after Houthi rebels stormed the capital Sanaa in September 2014.

Islamist-inspired fighters in the city have distributed pamphlets in mosques, warning men against enrolling in the new force to fight the Houthis, claiming it would "bring back tyranny," residents said.

Another man was shot dead on Saturday when gunmen attempted to kidnap him along with his father in Aden's Crater district, a security official said. The two belonged to the Shia Bohra minority.

Four members of that community have been kidnapped by "extremists" in the past days in Aden, three of whom have already been released, the official said.

Meanwhile, suspected al-Qaeda militants blew up a vacant police station in Huta, the main city in Lahj province which is controlled by loyalists.

Hadi sought refuge in Aden from the rebel-held capital last February, but a Houthi advance on the south in March forced him to flee to Riyadh.

He returned to Aden in November after loyalists backed by Saudi-led coalition forces pushed the rebels and their allies out of the city and four other southern provinces in the summer. 

But demands for greater autonomy and even full independence from groups which helped fight the Houthis have dogged his efforts to reassert this authority in an area that was only unified with northern Yemen in 1990.