Yemen's Iran-aligned Houthi movement said on Monday it had fired 17 drones and two ballistic missiles at Saudi targets, including towards Saudi Aramco refineries in Jubail and Jeddah.
There was no immediate Saudi confirmation. Saudi Aramco, the state oil firm, said when contacted by Reuters that it would respond at the earliest opportunity.
Houthi military spokesman Yahya Sarea said on Twitter the group had fired 17 drones and two missiles towards the kingdom.
The Houthis had also targeted "sensitive military sites" in the southern Saudi cities of Khamis Mushait and Jazan, according to Sarea.
The Saudi-led coalition that intervened in Yemen's war in 2015 against the Houthis said late on Sunday it had intercepted and destroyed six armed Houthi drones.
The coalition entered the war after the Houthis ousted the internationally recognised government from the capital Sanaa.