Oil advanced as the number of active drill rigs in the U.S. dropped to the lowest level since 2010.

Futures climbed as much as 1 percent in New York after capping the biggest weekly gain since 2011 on Friday. Rigs targeting oil in the U.S. fell by 26 to 734 last week, according to Baker Hughes Inc. International inspectors won’t be given access to Iran’s military bases in a deal with world powers to curb the nation’s nuclear program, a top Iranian commander said.

Oil has rallied about 30 percent from a six-year low in March on signs the idling of U.S. rigs is spurring a production slowdown that may ease the global surplus. The rally may still falter after American crude stockpiles swelled to the highest level in 85 years.

West Texas Intermediate for May delivery rose as much as 55 cents to $56.29 a barrel in electronic trading on the New York Mercantile Exchange and was at $56.26 at 9:47 a.m. Sydney time. The contract fell 97 cents to $55.74 on Friday. The volume of all futures traded was about 75 percent below the 100-day average. Prices climbed 7.9 percent last week.

Brent for June settlement gained 68 cents, or 1.1 percent, to $64.13 a barrel on the London-based ICE Futures Europe exchange. The European benchmark crude was at a premium of $6.22 to WTI for the same month.

Source: Bloomberg