Oil prices slipped on Tuesday as analysts forecast a weekly build in U.S. crude stockpiles, but prices remained close to four-year highs on worries that global supplies will drop due to Washington's sanctions on Iran. "This is the market catching its breath," said Gene McGillian, director of market research at Tradition Energy in Stamford, Connecticut. Still, oil prices drew support from worries that Iranian production will drop sharply after U.S. sanctions go into effect on Nov. 4. Also, global demand has remained strong in the face of trade tensions. International benchmark Brent dipped 22 cents to $84.76 per barrel by 10:55 a.m. EDT (1455 GMT) a day after reaching a four-year high of $85.45. U.S. West Texas Intermediate (WTI) crude futures fell 25 cents to $75.05 a barrel. U.S. crude hit a four-year high of $75.91 during the session. Five analysts polled by Reuters forecast that U.S. crude and gasoline stockpiles rose last week, while distillate inventories declined. Five analysts estimated that crude stocks rose about 1.1 million barrels in the week ended Sept. 28. Industry group the American Petroleum Institute (API) reports its U.S. inventory data Tuesday afternoon, and the U.S. government reports its data on Wednesday morning. Crude prices have roughly tripled from lows hit in January 2016, as the Organization of the Petroleum Exporting Countries and allies led by Russia have cut oil output. Oil market sentiment was lifted by a last-gasp deal to salvage NAFTA as a trilateral pact between the United States, Mexico and Canada. Prices have also been buoyed by looming U.S. sanctions against Iran's oil industry, which at its peak this year supplied nearly 3 percent of the world's daily consumption. Reuters survey of OPEC production found Iranian output in September fell by 100,000 barrels per day, while production from the group as a whole rose by 90,000 bpd from August. 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 take effect on Nov. 4. Many analysts say OPEC will struggle to cover a decline in exports from Iran. Britain's Barclays bank, however, said "OPEC has ample spare capacity". Soaring crude prices and weak emerging market currencies may erode economic growth. "Softening demand growth and new supply should cool the bullish sentiment and push prices lower by the end of the year," Barclays said.