Yemen's main warring factions endorsed a U.N.-brokered humanitarian truce from midnight on Friday although heavy fighting on the ground and Saudi air strikes carried on relentlessly.
The week-long truce will end at the same time as the Muslim holy month of Ramadan and aims to get aid to some 21 million Yemenis. All sides said they hoped a full ceasefire would follow.
A Saudi Arabia-led coalition of Arab states has been bombing the Iranian-allied Houthi rebel movement since late March in a bid to restore to power Yemen's President Abd-Rabbu Mansour Hadi, who has fled to Riyadh.
The dominant Houthis shelled residential areas in the southern port of Aden overnight and pushed further into Yemen's eastern Hadramawt desert, the center of the country's modest oil resources, fighting tribal militiamen, a local official said.
The Saudi-led campaign of air strikes targeted the capital Sanaa on Friday and hit mainly central and southern cities overnight.
The Arab coalition has pounded the Houthis and their army allies from the air since March 26 as part of a bid to restore exiled president Hadi to power. The air raids and fighting have killed more than 3,000 people since then.
"We hope this truce will be the beginning of the end of the Saudi aggression and the end of the violation of United Nations conventions that the war of aggression on Yemen has seen," a top Houthi leader, Mohammed al-Houthi said in a statement.
The party of Yemen's ex-president Ali Abdullah Saleh, whose loyalists in the military have been a major ally in the Houthi's advance in Yemen's south, also welcomed the pause in fighting.
U.N. envoy Ismail Ould Cheikh Ahmed clinched the deal after intensive discussions with Houthi leaders on Thursday.
He told Reuters that the more thorny political discussions would wait until after the humanitarian work was done.
Yemen's government has demanded that the Houthis conform to a U.N. Security Council Resolution in April which called on them to quit seized land and release prisoners.
"We must distinguish between the so-called humanitarian truce which has been insisted upon by the United Nations for a while and what we insist upon and hope for: that there will be a full truce with a comprehensive ceasefire including the withdrawal of forces," Yemeni Foreign Minister Riyadh Yasseen told state-owned Saudi Ekhbariya TV on Thursday.
The Houthis do not agreeing to those demands and view their takeover of the capital in September and spread across the country as part of a revolution against a corrupt government backed by the West.
