Saudi oil loadings sent to the Red Sea port of Yanbu resumed after a brief halt that sent oil prices surging, two sources told Reuters on Thursday.

Loadings were halted after staff had been evacuated, one of the sources said, after a drone crashed at Saudi Aramco's SAMREF refinery at the port earlier on Thursday.

An industry source said there was minimal impact on the refinery, but the damage was still being assessed.

Aramco, the world's top oil exporter, is trying to boost crude exports via Yanbu to offset the Strait of Hormuz disruption, with loadings seen rising to record volumes in March. Most of the cargoes are destined for Asia.

Iran has previously warned that the SAMREF refinery would be attacked in retaliation to Israel's attack on its South Pars gas field, a major escalation in the war with the U.S. and Israel.