Pakistan will not send its troops to Yemen and prefers to stay neutral in the "sensitive issue" saying that Saudi Arabia had adequate resources for its own defence.

The Pakistani parliament adopted a resolution on Yemen, urging the government to stay out of the conflict, despite a Saudi request to join the coalition forces against the Houthis.

Pakistan which had earlier expressed "unequivocal support for the Kingdom of Saudi Arabia" hopes to resolve differences peacefully in the "deteriorating security and humanitarian situation" which has "implications for peace and stability of the region".

Information secretary Senator Mushahidullah Khan said in a statement that Pakistan will negotiate for peace in the conflict or else "the Muslim world will blame Pakistan for acting as a silent spectator".

He said Pakistan's troops are already protecting the holy places in Saudi Arabia which "is our religious responsibility".

In the daily media briefing at Riyadh, Saudi military spokesperson Brigadier General Ahmed Asiri said Pakistan's non-participation in the operation would not affect the coalition's work.

The coalition forces are blocking Houthi supply routes to Shabwah and Dhala in Yemen, Asiri said while accusing the Houthi militia of preventing essential oil supplies from reaching Yemeni civilians.

The Houthis were using schools and playing fields as shelters, as well as stores for ammunition.

Coalition air strikes targeted a stadium in Aden where the Houthi militia and forces allied to the deposed Yemeni President Ali Abdullah Saleh stored ammunition and weapons.

"Targeting the infrastructure is not one of our goals, but it is being done out of necessity."

The Houthis are taking refuge in various civilian structures including public schools and sports complexes because they are on the run, said Asiri. "We will target them wherever they are."

The first Red Cross plane carrying medical aid into Yemen has landed in Sanaa airport, bringing in medical supplies desperately required.

More than 600 civilians and combatants have been killed in the two-week-long battle that has pitched the Saudi-coalition against Iranian-backed Shiite Houthi rebels fighting forces loyal to the country's internationally recognised president Abed Rabbo Mansour Hadi.

Saudi Arabia sees the rebels as proxies for regional Shiite powerhouse Iran seeking to destabilise the region but Tehran has denied any role and has so far restricted itself to denouncing the coalition action in Yemen.