Saudi-led warplanes intensified their air strikes against Yemeni rebels in the capital Wednesday, fuelling panic as political efforts to end a war that has displaced half a million people foundered. The Arab coalition has waged an air campaign against the Iran-backed Shiite rebels since March 26 in an effort to restore the authority of exiled President Abedrabbo Mansour Hadi, who fled to Riyadh. After a five-day humanitarian ceasefire expired at the weekend, the Saudi-led coalition resumed bombing several cities including the capital, accusing the rebels of having violated the truce.