Saudi Arabia intensified its airstrikes against the main Shiite rebel stronghold in Yemen, with warplanes carrying out more than 50 airstrikes strikes overnight and during the early hours on Friday, Saudi and Yemeni officials said.
The air strikes throw into question the future of a 5-day conditional ceasefire announced a day earlier by U.S. Secretary of State John Kerry and the Saudi foreign minister so that humanitarian aid can reach millions of civilians caught up in the conflict that has killed more than 1,400 people.
The Saudi-led military coalition said the airstrikes in the northern province of Saada were in response to cross border attacks by the rebels targeting Saudi Arabian cities near the frontier.
Saudi airstrikes have been pummeling Saada - which is the stronghold of Shiite rebels known as Houthis - for more than a month since the start of a campaign against the rebels, who are allied with forces loyal to ousted President Ali Abdullah Saleh.
On Friday, Saudi Press Agency reported that warplanes destroyed a landmine factory, a telecommunications complex and command centers. Yemeni officials said that in addition to the more than 50 airstrikes, helicopters dropped leaflets calling on residents to stay away from rebel positions and houses. They spoke on condition of anonymity because they were not authorized to speak to the media.
The Houthis and Saleh's forces overran Sanaa, the Yemeni capital, last September and are currently engaged in an offensive in southern Yemen and Aden - its main city. The offensive forced internationally-recognized President Abed Rabbo Mansour Hadi to flee the country in March and seek exile in the Saudi capital.
With airstrikes destroying large stockpiles of Houthi weaponry, the rebels responded by carrying out cross-border attacks targeting Saudi cities near the Yemeni frontier.
On Tuesday, Houthis fired rockets and mortars into Saudi Arabia, killing at least three people.
The Coalition spokesman, Saudi Brig. Gen. Ahmed Asiri, vowed a "harsh response'' to the attacks and said the Houthis "made a mistake by targeting Saudi cities.''
The intensified airstrikes cast a shadow over a ceasefire announced Thursday in Riyadh by Kerry and the Saudi foreign minister. The reprieve is dependent on whether the Houthis and their allies also agree to halt fighting.
Hamed al-Bokheiti, a spokesman for the Houthi movement in Sanaa, was dismissive Thursday of the cease-fire.
"What cease-fire are we talking about? Airstrikes are continuing unabated,'' he told The Associated Press by telephone.