The Saudi Arabian Civil Defence sent an all clear on Tuesday after issuing alerts for potential danger in six cities including Yanbu, the kingdom’s main Red Sea oil port, where millions of barrels a day are loaded.

Saudi Civil Defence said the danger had passed in Jeddah, Abha, Jazan, AlUla and Taif after the areas received emergency alerts amid an uptick in attacks by Yemen’s Iran-aligned Houthis.

The Houthis have stepped up attacks on Saudi cities and energy infrastructure while advancing along Yemen’s Red Sea coast towards the Bab el-Mandeb Strait, a key shipping route.