London (CNN Business) 1. Tanker trouble: US crude oil futures surged as much as 4% on Thursday following reports that two tankers had been attacked in the Gulf of Oman.

United Kingdom Marine Trade Operations, which monitors security in the region, said it was aware of an incident, and that Britain and its partners were investigating.

An advisory from the agency indicated the incident had occurred near the Strait of Hormuz, a vital trade artery through which roughly 30% of the world's sea-borne crude oil passes.

The waterway links the Gulf of Oman and the Persian Gulf, separating Oman from its eastern neighbor, Iran.

US crude futures had been trading near their lowest levels in five months. But they rebounded as traders reacted to reports of the attacks, gaining 2.3% to trade at $52.34 a barrel by 4:35 a.m. ET.