Saudi Arabia announced a five-day, renewable cease-fire in Yemen's war on Thursday to allow aid for civilians caught in a humanitarian crisis from the conflict. But the Saudi foreign minister said the truce would depend on the Shiite Houthi rebels' cooperation.The announcement came as battles raged in several parts of Yemen between forces loyal to the nation's internationally recognized president and the Shiite rebels and their allies. Military and security officials said the rebel forces advanced on the suburb of Dar Saad north of the strategic port city of Aden on Thursday, while fighting intensified in the nearby provinces of Abyan and Taiz.Addressing a joint news conference with U.S. Secretary of State John Kerry, Saudi Foreign Minister Adel al-Jubeir said the oil-rich kingdom would halt airstrikes in Yemen because it is determined to expand relief assistance to the Yemeni people. Saudi Arabia will provide $274 million in new assistance, he said.Kerry said the "humanitarian pause" would not start for several days, enough time for diplomatic efforts to convince the Houthis and their backers to accept the terms of the deal. He said aid organizations also needed time to coordinate the best strategy for getting food, fuel and medicine into and around the country."We strongly urge the Houthis and those who back them ... not to miss this major opportunity to address the needs of the Yemeni people and find a peaceful way forward," Kerry said, speaking in the Saudi capital, Riyadh.Kerry said he had spoken with Iranian Foreign Minister Mohammad Javad Zarif earlier this week. Kerry and al-Jubeir said they would provide an update Friday in Paris, where they will gather with the foreign ministers of other Arab countries. Iran gives the rebels political backing and Saudi Arabia and the U.S. say it also provides them with weapons, a claim Tehran denies.The Saudi-led campaign of airstrikes, which began on March 26, along with fighting on the ground has pushed Yemen toward a humanitarian disaster, the U.N. and other aid officials have warned for weeks. In the past six weeks, more than 1,400 people have been killed and 6,000 wounded, many of them civilians, the U.N. humanitarian coordinator in Yemen, Johannes van der Klaauw, said on Thursday.More than 300,000 others have fled their homes. The turmoil has disrupted crucial imports and internal transportation, causing shortages of fuel, food and medicines.Yemen was already the Arab world's poorest nation and has long been plagued by political dysfunction and violence by al-Qaida's most lethal branch.Several weeks ago, Saudi Arabia said it was dialing back its air campaign, but it quickly revved back up again when the rebels and pro-Saleh forces pressed ahead with their offensive south.Kerry, who earlier met with Saudi King Salman, expressed hope this time would be different."We particularly welcome a new Saudi initiative to try and bring about a peaceful resolution," Kerry said.In Tehran, the chief of Iran's Red Crescent society, Ali Asghar Ahmadi, also said a ship was being loaded with 2,500 metric tons of aid, including medicine and food, intended for Yemen.Van der Klaauw, the U.N. official, said he was "gravely concerned" by reports from Aden of the number of people killed and injured in the fighting, Wednesday."Civilians were reportedly targeted while they were trying to flee to safer areas, having been trapped in Aden with limited or no access to water, food and health care for weeks," he said.