The raids targeted Sanaa, the rebel-held capital, according to Saudi Arabia's Al Ekhbariya TV, which tweeted "the start of air strikes on Huthi camps and strongholds in Sanaa" around midnight.

The attacks began shortly after the Iran-backed Huthis announced a three-day truce and offered peace talks on condition that the Saudis stop their air strikes and blockade of Yemen and remove "foreign forces".

Rebel reports of casualties could not be independently confirmed.

The Huthi truce followed a wave of drone and missile attacks on Saudi targets on Friday, including an oil depot near Jeddah's Formula One track that turned into a raging inferno during televised practice sessions.

It was announced on the seventh anniversary of the intervention led by oil-rich Saudi Arabia in Yemen, its impoverished neighbour, after the Huthis seized Sanaa in 2014.

The conflict has killed hundreds of thousands of people directly or indirectly and displaced millions, creating what the United Nations calls the world's worst humanitarian crisis.

The Huthis have turned down an invitation to peace talks in Riyadh, scheduled for the coming days, to be hosted by the six-nation Gulf Cooperation Council.