Russia has begun shipping clean oil via the Baltic after a contamination problem disrupted flows for three weeks. It is working to resume pipeline supplies to Europe, although traders said this might take several more weeks to fix.

Two industry sources said Hungarian energy company MOL was receiving oil via Druzhba as part of a test to see whether it could be processed by the equipment at its sole Danube refinery.

Ships were moving inbound on Monday along the Houston Ship Channel after a Friday collision between a barge and deep-draft ship spilled petrochemicals into the waterway, closing ship traffic in both directions, the US Coast Guard said.

Saudi Arabia said on Monday that two of its oil tankers were among those attacked off the coast of the United Arab Emirates. It described the attack as an attempt to undermine the security of crude supplies amid tensions between the United States and Iran.

Royal Dutch Shell Plc began restarting the gasoline-producing unit at its 218,200 barrel-per-day (bpd) Norco, Louisiana, refinery on Sunday, sources familiar with plant operations said on Monday.