Yemen fell quiet on Wednesday for the first time since a Saudi-led coalition launched airstrikes against Iran-backed rebels on March 26, as a humanitarian truce appeared to be holding.

The cease-fire began at 11 pm, said Brigadier General Ahmed Asseri, spokesman for a Saudi-led coalition that has been striking Yemen's Houthi rebels since March 26, but clashes persisted after that in some areas.

It is intended to allow the shipment of food and medicine to the country - which aid groups warn faces a humanitarian catastrophe after more than seven weeks of war - but the cease-fire will end if the Houthis do not also lay down arms, Riyadh has warned.