Oil markets rose today, with Brent crude holding above $85 and near four-year highs reached the previous day as markets prepare for tighter supply once US sanctions against Iran kick in next month. 

International benchmark Brent crude oil futures were at $85.04 per barrel in early trade, up six cents from their last close, and not far off the $85.45 peak reached in the previous session, the highest since November 2014. 

Brent has risen by around 20% from its most recent lows in August. 

US West Texas Intermediate (WTI) crude futures were up 28 cents, or 0.4%, at $75.58 a barrel. WTI is up about 17% since the middle of August. 

Sentiment was lifted by a last-gasp deal to salvage NAFTA as a trilateral pact between the US, Mexico and Canada, rescuing a $1.2 trillion a year open-trade zone that had been about to collapse. 

More fundamentally, oil markets have been pushed up by looming US sanctions against Iran's oil industry, which at its most recent peak this year supplied almost 3% of the world's almost 100 million barrels of daily consumption. 

Trade data showed Iran's seaborne exports in September were just 1.6 million barrels per day, the lowest level since mid-2016.

"Oil prices continue to climb, supported by the nearing Iran embargo and related supply concerns," said Norbert Ruecker, head of commodity research at Swiss bank Julius Baer.

"The supply situation looks fragile indeed, as any additional shortfall such as a deterioration of the situation in Venezuela would tighten oil supplies."

HSBC said in its fourth quarter Global Economics outlook that "our oil analysts believe there is now a growing risk it (crude) could touch $100 per barrel". 

Washington's sanctions are set to start on November 4, and analysts say there may not be enough spare production capacity in the short-term to meet demand, potentially requiring large storage drawdowns. 

The Organisation of the Petroleum Exporting Countries (OPEC), of which Iran is a member, has struggled to replace export falls from Iran, according to a Reuters survey published this week. 

With crude prices soaring and many currencies in emerging markets, including India's rupee and Indonesia's rupiah declining, analysts warn that economic growth may be eroded.