Oil in London traded near a two-month high as Iranian crude and condensate exports fell to their lowest level in more than two years, showcasing concerns over a potential supply shortfall once U.S. sanctions on the Middle East nation’s shipments start in November.

Brent futures gained as much as 0.9 percent. Iran shipped just under 2.1 million barrels a day of crude and condensates in August, the lowest level since March 2016, ship-tracking data compiled by Bloomberg show. Still, Russia kept pumping oil near post-Soviet records last month, while OPEC output rose to its highest level this year, according to Bloomberg’s monthly survey.

Oil rose last month as supply concerns intensified before renewed American sanctions -- aimed at curbing Iranian exports -- kick in, adding to concerns over Venezuela’s plunging production. Traders and analysts are increasingly scrutinizing Saudi Arabia and Russia’s output data for signs they will fill potential gaps in supply.

“Underpinning the prevailing bullish sentiment is the increasingly supportive supply outlook,” PVM Oil Associates analyst Stephen Brennock wrote in a report. “Much of this owed to the downswing in Iranian oil shipments.”

Brent futures for November settlement traded 54 cents higher at $78.18 a barrel on the ICE Futures Europe exchange at 2:24 p.m. in London, earlier touching $78.31 a barrel. With the expiry of the October contract on Friday, the Brent futures curve is now fully backwardated -- with later contracts trading lower than nearer ones. This is an indication of tight supply.

West Texas Intermediate for October delivery added 14 cents to $69.94 a barrel on the New York Mercantile Exchange. The contract gained 1.6 percent last week. Total volume traded was about 54 percent below the 100-day average. Monday is Labor Day in the U.S. And Canada, with WTI crude and other CME energy contracts halting trade at 1 p.m. New York time. ICE Brent will close early at 1:30 p.m. New York time.

The Brent contract traded at an $8.65 premium to WTI for the same month, the widest since June. The U.S. marker is lagging Brent as American producers keep pumping crude at record levels near 11 million barrels a day.

Russia, the main beneficiary from its deal with OPEC and its allies to increase output, pumped an average of 11.21 million barrels a day, according to data from the Energy Ministry’s CDU-TEK unit. Libya’s 310,000 barrel-a-day increased lead OPEC’s combined monthly output 420,000 barrels a day higher to 32.74 million barrels a day, a Bloomberg survey showed.

Here are some key oil-market figures, news and events:

• Tropical Storm Gordon formed over the Upper Florida Keys, and was headed for the gulf of Mexico. Click here to see a map of the storm’s path and to access functionality showing energy assets in its trajectory.
• The U.S. heating oil crack gained to its highest intraday level since June early Monday, at $25.33 a barrel.
• The North Sea Buzzard oilfield, which is said to be shut since August 31, is due to resume output later this week following planned maintenance,