More than a hundred people have died and over 300 others were injured in a number of air raids by Saudi Arabia.
The Yemeni capital of Sana'a and the southern city of Ta'izz were targeted, with nearly 70 people killed In an attack on on arms depot near the capital.
"The latest reports show that up to 100 people were killed while nearly 300 others injured due to Monday's massive blasts caused by the Saudi-led airstrikes on arms depots," directors of four major hospitals in Sana'a told Xinhua News Agency.
"Hundreds of injured people have been taken to different hospitals in Sana'a. The number of casualties may rise as many injured were in critical condition with no sufficient medical care due to shortages of medicines," said Tamim, a senior medical official.
Yemen's official Saba News Agency, controlled by the Shia Houthi group, confirmed Monday's death toll in a text message.
A series of massive explosions sent debris crashing into a residential area at the foot of the mountain, according to Press TV.
Medical sources said most of the people killed and wounded in the airstrikes were civilians.
The airstrikes stopped hours before the UN envoy Ismail Ould Cheikh Ahmed arrived in Sanaa to begin preparations for a truce and to restart talks between forces loyal to exiled President Abed Rabbo Mansour Hadi and Houthi Shia rebels.
"We will discuss the humanitarian truce and the Yemeni parties' return to the negotiating table," he said.
The strikes overnight, at dawn and until midday targeted weapons depots and other military facilities north and south of the capital, the military said.
The ceasefire, which is to begin at 11pm (9pm GMT) is meant to help ease the suffering of civilians in Yemen, the poorest country in the Arab world.
Saudi Foreign Minister Adel al-Jubeir said that his country would implement the truce in order to allow humanitarian organizations to bring in aid.
According to the latest UN figures, the Saudi military campaign has so far claimed the lives of over 1,400 people and injured nearly 6,000 people, around half of them were civilians.