Saudi Arabia said Friday that a unilateral cease-fire in Yemen would start on May 12 and urged Shiite Muslim rebels and their allies to stop fighting.
It was unclear if the Iran-backed insurgents known as Houthis were prepared to lay down their arms.
At a news conference with Secretary of State
The announcement in Paris came hours after the Saudi-led coalition carrying out airstrikes in Yemen declared a rebel stronghold along the kingdom's southern border a "military target" and gave residents an ultimatum to leave the region by nightfall. The ultimatum was reported by state TV.
The escalation in the northern Yemeni province of Saada came in response to recent cross-border attacks by the Houthis on Saudi cities near the frontier, to which the coalition has vowed a "harsh response."
Yemeni officials said that more than 50 airstrikes hit Saada overnight and in the early morning. The official Saudi Press Agency reported that warplanes destroyed a land-mine factory, a telecommunications complex and command centers in Saada.
Jubeir and Kerry said Thursday that they were working on a cease-fire but still needed time to flesh out the details.
On Friday in Paris, where they gathered with other Arab foreign ministers, Kerry said the cease-fire was conditioned on no bombing, no shooting, no repositioning of troops and no movement of heavy weapons.
"A humanitarian catastrophe is building," Kerry warned, saying civilians were running out of food, fuel and medicine, and that aid groups needed to be allowed to get supplies into and around the country.