Saudi-led air strikes hit military bases in the Yemeni capital Sanaa and rival militias battled near the country's border with the kingdom on Wednesday, hours before a U.N.-mediated truce was due to take effect.
Residents said the air raids hit the sites in the early hours of the morning, the latest in a series of thousands of air strikes during a 19-month military intervention by Saudi Arabia and Arab allies into Yemen's civil war.
Despite the coalition's support, forces loyal to the internationally recognized exiled government have made few recent gains against their foes in the armed Houthi movement and army units based in Sanaa.
Yemen's pro-Houthi military said late on Tuesday that it had fired rockets at a Saudi army base and that its forces had repelled an attempt by Saudi-backed government forces to seize a strategic intersection connecting two far northerner provinces.
Several previous ceasefires have failed to pave the way for an end to the conflict but have significantly slowed fighting in the war which has killed at least 10,000 people.
President Abd-Rabbu Mansour Hadi told state news agency Saba on Wednesday that he expected his foes would violate the truce.
"We don't expect from them today anything more than prevarication and procrastination," Hadi was quoted as saying after meeting the American and British ambassadors.
The parliament in Sanaa, in which pro-Houthi MPs hold a majority, called on Wednesday for a "full commitment" to the truce, a day after a Houthi-led political council in the capital said it would comply.
Diplomats hope the 72-hour truce beginning at midnight will be extended by the warring parties and open the way for aid supplies as disease and hunger are spreading in the impoverished country.
The World Health Organization reported an outbreak of cholera in Sanaa this month and the U.N.'s Food and Agriculture Organization said that the war has halved cereal production and that 1.3 million Yemeni children are acutely malnourished.
"The fighting is still going on in many areas," the U.N. humanitarian coordinator for Yemen, Jamie McGoldrick, told reporters in Geneva on Wednesday.
"As we saw in previous ceasefires, not all parties accept it ... We hope that it does kick in and there is a chance that this holds and we can do more work and reach more areas."