At least 15 people have been killed and more than 40 others wounded after clashes erupted around the Yemeni interior ministry in the capital Sanaa, security officials say.

The clashes erupted on Tuesday between armed men who are supporters of former president Ali Abdullah Saleh and the police guarding the ministry.

The assailants, who had previously worked unofficially in the police department, had been surrounding the ministry's headquarters in the al-Hasaba district since Sunday, demanding that they be enrolled into the country's police force.

The exchange of fire using automatic rifles was heard intermittently throughout the morning, witnesses said.

The attackers had served in the police when it had been led by Mohammad Abdullah al-Qawsi during the rule of Saleh, security sources told the AFP news agency.

Qawsi had promised to recruit them officially before President Abdrabuh Mansur Hadi sacked him in May.

The assault on Tuseday was the second attempt to take control of the building. The gunmen had originally observed a sit-in, before setting two-day ultimatum for their demands to be met on Sunday.

They demanded that they be paid compensation and be employed officially in the police department.

Based on the agreement that saw Saleh replaced as president by Hadi, after a popular uprising against the former leader, the current president is obliged to restructure the military and security forces.