The runway was hit by two missiles, witnesses said, a day after the civil aviation authority in Sanaa announced it would
temporarily reopen the airport, which has been targeted frequently by air strikes.

 Earlier today, warplanes hit a nearby airbase, following a night of intensive bombardment of Shiite Huthi rebel positions in their northern stronghold of Saada.

 Saudi Arabia yesterday announced a humanitarian ceasefire in Yemen starting May 12, but has vowed to step up retaliatory strikes on the rebels, which it accuses of launching cross-border attacks on the kingdom.

 Huthi militias in Yemen have crossed a "red line" and will pay a high price for their deadly bombardments of Saudi Arabia, the Saudi-led coalition said .

"The equation is different, the confrontation is different, and they will pay a harsh and expensive price,"coalition spokesman Brigadier General Ahmed al-Assiri told .

"The safety of Saudi Arabia is a top priority for the coalition and the Saudi armed forces. It is a red line they crossed." Shells fired from Yemen killed five people in the kingdom's Najran region yesterday in a second day of cross-border bombing blamed on the Iran-backed Shiite Huthi rebels, civil defence authorities said.

Three others died in a mortar and rocket attack on Najran on Tuesday, the first time the Huthi rebels attacked a Saudi community since the Saudi-led coalition on March 26 began air strikes against the Huthis and their allies in neighbouring
Yemen.

In Jazan district adjacent to Najran, a missile killed a husband and wife on Tuesday, the civil defence department
said. It was "killing for the sake of killing," Assiri said.
   

 "Now the confrontation is targeting Saudi Arabia's borders, targeting Saudi citizens, targeting the safety and security of Saudi cities. Here we confirm that this is unacceptable," the spokesman added.

 He said an operation to respond "starts now" and will target "all the leaders of the organisation, the areas they gather, their leadership locations, and the planners. And it will not be a limited operation."

 The Huthi stronghold of Saada, in northern Yemen, will be among the areas in the coalition's sights, Assiri said. Hours earlier, Saudi Foreign Minister Adel al-Jubeir proposed a five-day ceasefire to allow aid into Yemen but said the Huthis would have to abide by it.

 The coalition took action in March after Riyadh feared the Huthis would take over all of Yemen and pull it into the orbit
of the kingdom's Shiite regional rival Iran.