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.

The ISM’s U.S. factory index rose to 53.9 in December from 52.7 a month earlier, the Tempe, Arizona-based group’s data showed today. Readings above 50 signal expansion.

India’s Purchasing Managers’ Index rose the most in six months in December, HSBC Holdings Plc and Markit Economics said yesterday. China’s purchasing managers’ index rose to 50.3 in December from 49 in November, the Beijing-based logistics federation said Jan. 1. A number above 50 indicates expansion.

German unemployment fell more than forecast in December, adding to optimism that Europe’s economy will grow. The number of people out of work fell a seasonally adjusted 22,000 to 2.89 million, the Nuremberg-based Federal Labor Agency said today. The adjusted jobless rate dropped to 6.8 percent.

Futures also rose as the U.S. and its allies increased pressure on Iran to halt what they say may be a covert nuclear weapons program. Sanctions signed into law by President Barack Obama on Dec. 31 aim to deter dealings with the Iranian central bank. The European Union will be ready by Jan. 30 to decide whether to extend sanctions, Michael Mann, a spokesman for the EU, said yesterday.

Iran, OPEC’s second-largest producer, doesn’t intend to disrupt shipping in the Strait of Hormuz, Deputy Navy Commander Rear Admiral Mahmoud Mousavi said yesterday, according to Press TV. Almost 17 million barrels a day of crude moved through the channel connecting the Persian Gulf to the Gulf of Oman last year, the U.S. Energy Department said in an update on “world oil transit chokepoints.”

Crude oil for February delivery touched $102.88, the highest level since Nov. 17. Futures climbed 8.2 percent in 2011, the third consecutive annual increase.

Brent oil for February settlement advanced $4.09, or 3.8 percent, to $111.47 a barrel on the London-based ICE Futures Europe exchange. The European benchmark contract’s premium to West Texas Intermediate futures was at $8.74, down from a record $27.88 on Oct. 14.