Fighting and Saudi-led air strikes targeting Houthi rebels have struck across Yemen, officials said, as the United Nations said that Saudi Arabia had agreed to completely fund a $273.7 million appeal for emergency humanitarian aid to the county.

In the southern port city of Aden, Yemen’s second largest, forces loyal to President Abd-Rabbu Mansour Hadi regained control on Sunday of part of the coastline that had been held by forces loyal to rebel leader Abdul-Malek al-Houthi and former president Ali Abdullah Saleh, security officials told the Associated Press news agency.

The gained positions allow them to attack the rebel-held airport and cut off supplies to anti-Hadi forces, they said.

The news comes as a Yemeni commander of a vast military district covering half the country’s border with Saudi Arabia pledged support on Sunday to exiled President Hadi, local officials said.

The announcement puts at least 15,000 troops in the desert and mountain border area on the same side as Saudi Arabia, which backs Hadi and has waged an inconclusive three-week bombing campaign against Houthi rebels, who are allied with Iran.

“Brigadier General Abdulrahman al-Halily of the First Military District announced today his support for constitutional legitimacy as represented by President Hadi,” one of the officials told Reuters.

Most of Yemen’s military is loyal to powerful ex-president Ali Abdullah Saleh, whose forces are fighting alongside the Houthis in battles stretching across Yemen’s south and east.

But the defection of the northeastern troops brings to about 10 the number of divisions that back Hadi.

The combat, which intensified in late March when Saudi-led coalition began launching air strikes, pits the Houthis against forces loyal to Hadi.

On Sunday, officials said that rebel forces, who were trying another push to take the Dar Saad area, just north of Aden, had failed. They spoke on condition of anonymity because they were not authorised to brief journalists.

Meanwhile in Amman, the United Nations said Saudi Arabia had agreed to fund completely a $273.7 million appeal for emergency aid to avoid a humanitarian catastrophe inside Yemen.

The UN issued the urgent appeal last week, saying it was needed to save lives and protect some 7.5 million people affected by the conflict. Al Jazeera