Saudi stocks .TASI opened 2.3% lower on Sunday, reacting to news of attack on two plants at the heart of the kingdom’s oil industry on Saturday, knocking out more than half Saudi output.

Axar.az reports citing foreign media.

Other Gulf markets also reacted negatively to the attack with Kuwait’s premier index .BKP down 1.1% and Dubai stocks .DFMGI falling 0.8%.

Saudi Basic Industries (2010.SE), the kingdom’s biggest petrochemicals firm, plunged 3.5% after it said it had curtailed feedback supplies by about 49%, following the attack.

The drone attacks were claimed by Yemen’s Houthi group, the group’s military spokesman said on Al Masirah TV.