Shipping industry seeks to combat dark oil transfers at sea

As both Iran and Venezuela have boosted exports, cargo trackers have detected an increased number of STS transfers in open waters over the last year. They take place off Malaysia's coast, at locations off Africa and also in the Caribbean, shipping and trading companies say.

LONDON/MEXICO CITY: Top oil shipping companies say they have tightened operational guidelines and deployed technology to prevent accidental breaches of sanctions, as the countries hit by ever tougher restrictions fight back with elaborate strategies to dodge them.

Washington has ramped up shipping-related sanctions over the last two years to make it harder for countries, such as Iran and Venezuela, to export the oil that provides their main source of revenue.