US Cash Crude-Mars Sour eases to weakest in almost two weeks

March 10 (Reuters) - Cash crude prices for Mars Sour, a key sour grade in the U.S., eased on Monday to their weakest in nearly two weeks, dealers said, an about-face for the grade that had just last week surged after the U.S. imposed tariffs on Mexico and Canada.

Mars Sour WTC-MRS eased 30 cents at a midpoint of a $1.35 premium to U.S. crude futures CLc1. It had previously reached as high as $2.75 cents a barrel last Tuesday.

President Donald Trump's imposition last week of a 25% tariff on imports from Mexico and Canada, with the exception of a 10% levy on Canadian oil, had pushed up spot prices for the coastal grade, which is an attractive alternative to Mexican grade Isthmus.

However, the grade has since eased after initial "panic-buying," market sources said.

Even so, over the weekend U.S. Commerce Secretary Howard Lutnick said Trump would not let up pressure on tariffs on Mexico, Canada and China.

On Friday, Russia's Deputy Prime Minister Alexander Novak said the OPEC+ group agreed to start increasing oil production from April, but could reverse the decision afterwards if there are market imbalances.

In refining, U.S. oil refiners are expected to have about 1.1 million barrels per day of capacity offline in the week ending March 14, increasing available refining capacity by 85,000 bpd, research company IIR Energy said on Monday.

Light Louisiana Sweet WTC-LLS for April delivery eased 3 cents at a midpoint of a $3.85 premium and was seen bid and offered between a $3.50 and $4.20 a barrel premium to U.S. crude futures CLc1

Mars Sour WTC-MRS eased 30 cents at a midpoint of a $1.35 premium and was seen bid and offered between a $1.25 and $1.45 a barrel premium to U.S. crude futures CLc1

WTI Midland WTC-WTM was little changed at a midpoint of a $1.20 premium and was seen bid and offered between a $1.10 and $1.30 a barrel premium to U.S. crude futures CLc1

West Texas Sour WTC-WTS eased 8 cents at a midpoint of a 75-cent premium and was seen bid and offered between a 60-cent and 90-cent a barrel premium to U.S. crude futures CLc1

WTI at East Houston WTC-MEH, also known as MEH, traded between a $1.35 and $1.55 a barrel premium to U.S. crude futures CLc1

ICE Brent May futures LCOc1 fell $1.08 to settle at $69.28 a barrel

WTI April crude CLc1 futures fell $1.01 to settle at $66.03 a barrel

The Brent/WTI spread WTCLc1-LCOc1 widened to last trade at minus $3.60, after hitting a high of minus $3.57 and a low of minus $3.66.