The leader of Yemen's Houthi rebel group has vowed that he will "never give in" to a Saudi Arabia-led air war, and said that Yemenis have the right to resist "aggression" by any means.

"Our Yemeni people will never give in," Abdelmalik al-Houthi said in an television address on Sunday, on the 25th day of the air strikes targeting his rebel group.

The Houthi leader vowed to put up tough resistance using "all means and options" available, without elaborating.

Saudi has accused the Houthis of forging an alliance with Iran to oust the government of President Abd-Rabbu Mansour Hadi.

On Sunday, Saudi-led coalition spokesman Ahmed Asseri said fighting and air strikes targeting Houthis have struck across Yemen.

He said that at least 106 air strikes have been launched against the Houthis in the cities of Sanaa and Sadaa, targeting storage facilities for "ballistic missiles."

In the southern port city of Aden, Yemen's second largest, forces loyal to Hadi regained control on Sunday of part of the coastline that had been held by Houthis forces and loyalists of 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.

Switching support

The Yemeni commander of a vast military district covering half the country's border with Saudi Arabia has also pledged his 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.

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Al Jazeera's Mohammed Vall, who is reporting in Jizan at the Saudi Arabia border with Yemen, said that while Hadi loyalists have gained ground, they still have no central commander to lead them.  

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

Also 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.

As fighting continues, the political party of Saled said on Sunday that it welcomes a UN resolution calling for ceasefire in the country, urging all involved in the conflict, including Saudi, to observe it.

"(The party) welcomes the UN Secretary-General's call to for a ceasefire from all sides and a return to dialogue under the auspices of the United Nations,'' it said. It added that it urged parties "inside and outside'' the country to respond to the call.

Pro-Saleh forces have been fighting alongside Houthis, who have seized the capital, Sanaa, and other cities.

Source: Agencies