SINGAPORE, March 12 (Reuters) - Chicago wheat futures slid on Tuesday, with the market facing pressure from slowing demand for U.S. cargoes amid stiff competition from suppliers in the Black Sea region.

Corn lost ground, while soybeans were largely unchanged with both markets being weighed down by ample world supplies.

FUNDAMENTALS

* The most-active wheat contract on the Chicago Board of Trade (CBOT) was down 0.3% to $5.45-3/4 a bushel, as of 0020 GMT. Corn slid 0.3% to $4.40-1/4 a bushel and soybeans lost quarter of a cent to $11.79 a bushel.

* Falling Russian wheat export prices and high supply in the global market are reducing demand for U.S. wheat.

* Private exporters cancelled sales of 264,000 metric tons of U.S. soft red winter wheat that had been booked for delivery to China, the U.S. Department of Agriculture (USDA) confirmed on Monday.

* It was the third cancellation in as many business days and the largest of the three, following two cancellations last week totalling 240,000 tons of soft red wheat sold to China.

* About 4% of winter cereals in Russia are in "poor and sparse" condition, the Russian Grain Union said on Monday, compared with a typical rate of 6% at this stage of the season.

* Near-record Brazilian supplies are weighing on soybean prices.

* The USDA slightly lowered its Brazilian soybean crop forecast, but its outlook was above many private estimates and reminded dealers of plentiful South American supplies.

* Sales of the 2023/24 soybean harvest in Brazil reached 36.6% of projected production, behind the historical average for the period but slightly ahead of last year at this time, according to agribusiness consultancy Safras & Mercado on Monday.

* Commodity funds were net buyers of CBOT corn, wheat and soyoil futures contracts on Monday and net sellers of soybean and soymeal futures, traders said.

MARKET NEWS

* A gauge of global stocks retreated for a second straight session on Monday, easing further from a record high ahead of U.S. inflation data this week which could heavily influence the Federal Reserve's interest rate path.

DATA/EVENTS (GMT) 0700 Germany HICP Final YY Feb 0700 UK Claimant Count Unem Chng Feb 0700 UK ILO Unemployment Rate Jan 0700 UK HMRC Payrolls Change Feb 1230 US Core CPI MM, SA; YY, NSA Feb 1230 US CPI MM, SA; YY, NSA Feb 1230 US CPI Wage Earner Feb (Reporting by Naveen Thukral; Editing by Sherry Jacob-Phillips)