Yemen's Houthi rebels reported dozens of Saudi airstrikes on Wednesday as daily attacks continued in a conflict that has reignited during the Middle East war, with hundreds of people killed in fighting near the Red Sea.

More than 40 attacks targeted several regions including the flashpoint areas of Taiz and Hodeida, the scene of fierce clashes between the Houthis and Saudi-backed government, the rebels said.

"It's a catastrophe, and the attacks are ongoing," said Mohammed Khudairi, one of nearly 20,000 who fled the fighting, according to the International Organization for Migration.

"We managed to leave, but others remain trapped there," he said at a displacement camp of wood-and-straw huts near Khokha, on the Red Sea coast.

The latest salvos in Yemen's previously dormant conflict come a day after the Iran-backed Houthis set oil sites ablaze and wounded 73 in their heaviest missile and drone attacks against Saudi Arabia in years.