Oil climbed to a six-week high after manufacturing in the U.S. and Asia expanded in December and as concern persisted that further sanctions against Iran may disrupt shipments.

Futures gained as much as 4 percent on the first day of trading this year as the Institute for Supply Management’s U.S. factory index rose more than expected, adding to increases in China and India. An Iranian military official warned the U.S. against sending an aircraft carrier back to the Persian Gulf.