LONDON- Oil prices rose slightly on Thursday, boosted by a decline in U.S. inventories, ongoing supply cuts from OPEC and its allies, and U.S. sanctions on Venezuela and Iran.

Brent crude futures were at $71.80 a barrel at 1313 GMT, up 18 cents from their last close and near Wednesday's five-month high of $72.27 a barrel.

U.S. West Texas Intermediate (WTI) crude futures were at $63.83 per barrel, up 7 cents.

Both contracts traded slightly lower earlier in the day.

U.S. crude inventories fell by 1.4 million barrels in the week to April 12, U.S. Energy Information Administration (EIA) data showed on Wednesday. 

"The latest weekly statistics on U.S. oil inventories were seemingly positive. All the major categories registered draws," Tamas Varga of London-based oil brokerage PVM said.

Gasoline stocks fell by 1.2 million barrels, and distillate stocks, which include diesel and heating oil, fell by 362,000 barrels, the EIA data showed.

Prices have been supported this year by an agreement reached by the Organization of the Petroleum Exporting Countries and its allies, including Russia, to limit their oil output by 1.2 million barrels per day (bpd).

Global supply has been tightened further by U.S. sanctions on OPEC members Venezuela and Iran.

Iran's crude exports have dropped in April to their lowest daily level this year, tanker data showed and industry sources said, suggesting a reduction in buyer interest ahead of expected further pressure from Washington. 

Indian refiners are turning to other OPEC members, Mexico and the United States to make up for any loss of Iranian oil. 

Spain's Repsol has suspended its swaps of refined products for crude with Venezuela's state-run oil company PDVSA , people familiar with the matter said, as U.S. officials weigh penalties for foreign firms doing business with Venezuela. 

Growing U.S. oil production and concerns over the U.S.- China trade dispute are keeping prices in check.

U.S. crude oil output from seven major shale formations was expected to rise by about 80,000 bpd in May to a record 8.46 million bpd, the EIA said in its monthly report on Monday.

Surging U.S. production has filled some of the gap in supplies, although not all of the lost production can be immediately replaced by U.S. shale oil due to refinery configurations.

(Reporting by Aaron Sheldrick, Colin Packham and Jane Chung; Editing by Joseph Radford and Mark Potter) ((colin.packham@thomsonreuters.com; +61-2 9321 8161; Reuters Messaging: colin.packham.thomsonreuters.com@reuters.net))