A Saudi-led airstrike campaign targeting Shia rebels who control much of Yemen has pushed them out of contested air bases, the kingdom said, a day after Yemen’s president said the aerial attacks will not stop until the rebels surrender.

Saudi Brigadier-General Ahmed bin Hasan Asiri said on Sunday the airstrikes had destroyed any jet fighter remaining in the Arab world’s poorest country.

The campaign, now entering its fourth day on Sunday, continued to target Scud missiles in Yemen, leaving most of their launching pads “devastated,” according to remarks carried by the state-run Saudi Press Agency.

There was no immediate comment from the Houthis, who began their offensive in September, seizing the capital, Sanaa, and later holding embattled President Abd-Rabbo Mansour Hadi under house arrest.

Dozens of civilians have been killed in the Saudi-led coalition’s air assault, and ground fighting has been reported between Houthi fighters and armed men supporting Hadi in the southern port city of Aden.