HOUSTON — The number of rigs exploring for oil and natural gas in the U.S. increased by 10 this week to 431.

A year ago, 862 rigs were active. Depressed energy prices have sharply curtailed oil and gas exploration.

Houston oilfield services company Baker Hughes Inc. said Friday 341 rigs sought oil and 89 explored this week for natural gas. One was listed as miscellaneous.

Among major oil- and gas-producing states, Texas and Oklahoma each gained four rigs; Colorado two and Louisiana one.

Alaska and New Mexico declined by two apiece.

Arkansas, California, Kansas, North Dakota, Ohio, Pennsylvania, Utah, West Virginia and Wyoming were unchanged.

The U.S. rig count bottomed out in May at 404.