A bomb ripped through the governor's temporary headquarters in Yemen's main southern city of Aden on Thursday, killing four people and injuring 10 others, security officials and medics said.

Governor Nayef al-Bakri was unharmed in the blast at the headquarters of the Aden Faculty of Administrative Sciences, which is housing the governor's offices, the sources told AFP.

It was the first such attack in Aden since pro-government forces retook the city from Houthi militias in mid-July.

The authorities could not immediately identify the perpetrators, the security officials said.

Bakri is known for his close ties to the al-Islah Party, seen as the country’s branch of the Muslim Brotherhood.

He was deputy governor of Aden until the Houthis advanced on the city in March after seizing the capital Sanaa.

Exiled President Abedrabbo Mansour Hadi later appointed him governor, rewarding him for remaining in the city during months of fierce fighting while many other provincial officials fled.

The recapture of Aden by loyalist forces supported by Saudi-led air strikes was a turning point in the conflict, paving the way for their advance across the south, although the Houthis still hold Sanaa.

After a string of victories, Yemeni government spokesman, Rajeh Badi, on Tuesday said that most provinces had been freed from the Houthis and that the anti-Houthi forces would now be looking to take back the cites of Sanaa, Amran and Saada, the capital of the Houthi northern heartland.

"We call on the Houthis to understand the lesson after their defeat in most of Yemen’s cities," he told Anadolu Agency speaking from Doha, Qatar.

"We urge them to implement UN Security Council resolution 2216," he said, adding that "any solution outside the Security Council resolution is completely unacceptable".

On 14 April, UNSC Resolution 2216 - which was drafted by members of a Saudi-led anti-Houthi coalition and submitted by Jordan - was endorsed by 14 countries at the United Nations Security Council.

The resolution called on Houthi forces to “immediately and unconditionally” end all violence, retreat from all areas of Yemen captured previously, return military equipment seized earlier and release all political detainees and child soldiers.

"We are seeking to liberate the whole of Yemen from the Houthis, not only Sanaa but also Amran and Saada… Sanaa is the political capital and the capital of all Yemenis."

The spokesman denied that the Houthi withdrawal from the south was "tactical," as they have claimed.

"This is not true, what is happening is a victory for the resistance and for the national army, it is also a large collapse for the Houthi militias and the pro-Saleh forces,” he added in reference to forces loyal to former president Ali Abdullah Saleh who has fought in alliance with the Houthis.