July 3 (Reuters) - Grades edged higher on Thursday, dealers said, as the spread between U.S. crude futures and Brent widened.

WTI at East Houston WTC-MEH, also known as MEH, rose 5 cents to its highest in nearly a month. Mars rose $1.

U.S. crude futures' discount to Brent widened to as much as minus $3.19, its most in 10 days. A wider spread makes U.S. grades more attractive to foreign buyers.

U.S. energy firms this week cut the number of oil rigs by seven to 425, their lowest since September 2021, energy services firm Baker Hughes said in its closely followed report on Thursday. Oil rig count is an indicator of future output.

Meanwhile, OPEC+ is set to announce another big output increase of 411,000 barrels per day for August as the oil producer group looks to regain market share, sources said, worrying markets about excess supply.

In the futures market, oil prices fell slightly on Thursday as investors worried that U.S. tariffs could slow energy demand ahead of the expected OPEC+ supply boost.

* Light Louisiana Sweet WTC-LLS for August delivery rose 35 cents to a midpoint of a $2.35 premium and was seen bid and offered between a $1.90 and $2.80 a barrel premium to U.S. crude futures CLc1

* Mars Sour WTC-MRS rose $1 to a midpoint of a $1.05 premium and was seen bid and offered between an 85-cent and $1.25 a barrel premium to U.S. crude futures CLc1

* WTI Midland WTC-WTM was unchanged at a midpoint of a 45-cent premium and was seen bid and offered between a 20-cent and 70-cent a barrel premium to U.S. crude futures CLc1

* West Texas Sour WTC-WTS was flat at a midpoint of a 25-cent discount and was seen bid and offered between a discount of 50 cents and parity to U.S. crude futures CLc1

* WTI at East Houston WTC-MEH, also known as MEH, traded between a 50-cent and $1.00 a barrel premium to U.S. crude futures CLc1

* ICE Brent September futures LCOc1 fell 31 cents to settle at $68.8 a barrel on Thursday.

* WTI August crude CLc1 futures fell 45 cents to settle at $67 a barrel on Thursday.

* The Brent/WTI spread WTCLc1-LCOc1 widened 4 cents to last trade at minus $3.14, after hitting a high of minus $3.04 and a low of minus $3.19.

(Reporting by Arathy Somasekhar in Houston; Editing by Sonali Paul)

((arathy.s@tr.com))