LONDON (Reuters) - The world’s oil supply cushion could be stretched to the limit due to prolonged outages, supporting prices and threatening demand growth, the International Energy Agency said on Thursday.

FILE PHOTO: Oil barrels are pictured at the site of Canadian group Vermilion Energy in Parentis-en-Born, France, October 13, 2017. REUTERS/Regis Duvignau/File Photo

The expected drop in Iranian crude exports this year due to renewed U.S. sanctions, coupled with a decline in Venezuela’s production and outages in Libya, Canada and the North Sea have driven oil prices to their highest since 2014 in recent weeks.

OPEC and other key producers including Russia responded to the tightness by easing a supply-cut agreement, with Saudi Arabia vowing to support the market as U.S. President Donald Trump accused the group of pushing prices higher.

The Paris-based IEA said in its monthly Oil Markets Report that there were already “very welcome” signs that output from leading producers had been boosted and may reach a record.

The global energy watchdog however said the disruptions underscored the pressure on global supplies as the world’s spare production capacity cushion “might be stretched to the limit”.

Spare capacity refers to a producer’s ability to ramp up production in a relatively short time. Much of it is located in the Middle East.

The IEA said OPEC crude production in June reached a four-month high of 31.87 million barrels per day. Spare capacity in the Middle East in July was 1.6 million bpd, roughly 2 percent of global output.

As U.S. sanctions on Iran are expected to “hit hard” in the fourth quarter of the year, Saudi Arabia could further ramp up output, which would cut the kingdom’s spare capacity to an unprecedented level below 1 million bpd, the IEA said.

Non-OPEC production including from surging U.S. shale also continued to rise, but the IEA said that might not be enough to assuage concerns.

“This vulnerability currently underpins oil prices and seems likely to continue doing so. We see no sign of higher production from elsewhere that might ease fears of market tightness,” it said.

The IEA maintained its 2018 oil demand growth forecast at 1.4 million bpd, but warned that higher prices could dampen consumption.

“Higher prices are prolonging the fears of consumers everywhere that their economies will be damaged. In turn, this could have a marked impact on oil demand growth.”

The IEA said Iran’s crude exports could be reduced by significantly more than the 1.2 million bpd seen in the previous round of international sanctions. Iran exports roughly 2.5 million bpd, most of which goes to Asia.

China and India, the world’s second and third largest oil consumers, could face “major challenges” in finding alternative crude oil following the drop in Iranian and Venezuelan exports, the IEA said.

Iranian crude exports to Europe dropped by nearly 50 percent in June, the IEA said, as refiners gradually wind down purchases before U.S. sanctions take effect in November.

For graphic on OPEC crude supply (Source: IEA) click reut.rs/2NLDrgP

For graphic on Iran crude oil loadings (Source: IEA) click reut.rs/2LaGKME

For graphic on U.S. crude oil production (Source: IEA) click reut.rs/2Lbsgwb