The price of oil fell below $103 per barrel Friday on ample supplies of crude and fuels.
Natural gas fell 1.7 cents to close at $4.542 per 1,000 cubic feet.
Benchmark U.S. crude for July delivery fell 87 cents to close at $102.71 a barrel in New York. The contract closed down 1.6 percent for the week, though it finished the month up nearly 3 percent.
Brent crude, a benchmark for international oil used by many U.S. refineries, fell 56 cents to close at $109.41 a barrel in London.
The price of crude was pulled down in part by the falling prices of wholesale gasoline and heating oil, suggesting that the U.S. has ample supplies of refined fuels. That could crimp demand for crude oil in coming weeks.
Crude supplies in the U.S. are also plentiful, but crude prices were pushed higher during the month because inventories at the U.S. trading hub where benchmark crude is priced have fallen sharply.
Next week traders are expected to focus on a string of macroeconomic reports, including a manufacturing report and employment data that could change expectations for gasoline, diesel and crude demand.
The average retail price of gasoline in the U.S. rose a penny Friday to $3.66 a gallon. That's 3 cents lower than a month ago and 4 cents higher than a year ago at this time.
In other energy futures trading on Nymex, wholesale gasoline fell 2.4 cents to close at $2.972 a gallon, and heating oil fell 3.2 cents to $2.888 a gallon.