UN Secretary General Ban Ki-moon has called for an immediate halt to the fighting in Yemen.

"The United Nations-supported diplomatic process remains the best way out of a drawn-out war with terrifying implications for regional stability," he said in a speech broadcast on C-SPAN radio.

Yemen is the poorest nation in the Middle East with levels of food insecurity that were higher than in the poorest parts of Africa, he noted.

Iran's Foreign Minister Mohammad Javad Zarif spoke to Ban urging cessation of hostilities and dispatching humanitarian aid for the Yemeni people.

Zarif indicated that Iran was willing to mediate dialogue and resolve the crisis in the Arab country.

Iran proposes a four-point plan emphasising the Yemeni nation's right to decide its own future free from foreign interference.

Iran's defence minister has accused the US and Israel of authorising the Saudi-led operation against Yemen.

At the Fourth Moscow International Security Conference on Thursday (16 April), Brig Gen Hossein Dehqan said not only will the Saudi regime fail to achieve its "illegitimate" purposes in Yemen, but will also suffer a heavy defeat.

A fate similar to that of former Iraqi dictator, Saddam Hussein, awaits Riyadh's ruler, he added.

Gaza offensive

The Iranian minister drew a parallel between Riyadh's air strikes and the Israeli offensive against the Palestinians in Gaza last summer, reports Iranian state media.

Dehqan called for an "all-inclusive government" through intra-Yemeni dialogue and free from foreign meddling.

Yemen's newly appointed Vice President Khalid Bahah said his government welcomes all initiatives aimed at resolving the conflict, but ruled out dialogue with the Houthis till they "stopped the killings".

Speaking to reporters at the Yemeni Embassy in Riyadh, he said his new government's absolute priority would be to provide humanitarian aid to all the needy people "in order to stop the situation from turning into a humanitarian catastrophe".

In another development, the Saudi-led coalition called upon commanders supporting former Yemeni president Ali Abdullah Saleh to surrender.

Brigade No 19 was the latest to join the "legitimate government of President Abed Rabbo Mansour Hadi" following brigades 123, 127 and 133, said Brig Gen Ahmad Al-Assiri, spokesperson of the Saudi coalition.

The coalition had destroyed the warehouses, buildings and arms depots where the rebels had hidden their ammunition, he said, adding that food supplies were being delivered to Yemeni citizens with the help of the popular committees and tribal communities.

Almost 1,000 civilians and combatants have been killed and thousands displaced in the three-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.