By Paul CarstenLONDON (Reuters) - Oil prices were steady on Tuesday, after a bump the previous day when fresh U.S. sanctions imposed on Iran increased concerns that supply might tighten, as global refining margins remained strong.Brent crude futures were down 5 cents to $74.73 a barrel by 1046 GMT. U.S. West Texas Intermediate crude futures were up 2 cents to $70.72 a barrel. Both contracts gained in Monday's session after a $2 drop last Friday."In the short term, I continue to think crude oil is looking for a base. The fresh U.S. sanctions announced on Iran overnight will likely assist with this as will the Iraqi oil minister's commitment to rein in its oversupply," said IG market analyst Tony Sycamore.On Monday, President Trump hit Iran with the second set of sanctions this month, maintaining pressure as he vies to shut down Iranian crude exports. The U.S. sanctioned oil brokers in the United Arab Emirates and Hong Kong, tanker operators and shipping companies in India, and the head of Iran's National Iranian Oil Company for their role in transporting Iranian oil.Iran is the third-largest producer in the Organization of the Petroleum Exporting Countries, pumping 3.2 million barrels per day in January, according to a Reuters survey of OPEC output.Also on Monday, the third anniversary of Russia's invasion of Ukraine, the EU listed 73 ships enabling sanctions evasion, known as the shadow fleet, while Britain sanctioned 40 vessels for transporting Russian oil.Western fuel demand strength also supported oil markets, some analysts said.investing.com