Three-month copper on the London Metal Exchange fell 0.9 percent to $8,455 a tonne by 0436 GMT, after reaching $8,679.50 on Friday, the highest since Sept. 16.

Prices are headed for the biggest monthly gain since October, with an increase of 11 percent.

The most-traded April copper contract on the Shanghai Futures Exchange gained 0.4 percent to 60,960 yuan ($9,600) a tonne. The exchange re-opened Monday after a week-long closure because of the Lunar New Year holiday.

European Union leaders will sign off on a permanent rescue fund for the euro zone at a summit on Monday, the first for this year, and are expected to agree on a balanced budget rule in national legislation.

Still, Greece's negotiations with creditors to prevent a disorderly default are hanging over markets.

"Whatever deal they cut at this point is will only extend the rope a little for Greece to hold on to," said Song Seng Wun, regional economist at CIMB Research in Singapore.

"They have to cut a deal without which all sides will lose."

The euro came off six-week highs against the dollar on Monday, as investors took profits made on its strongest weekly rally in more than a quarter and awaited a debt deal between Greece and its private creditors.

Money managers, including hedge funds and other large speculators, raised their net long position in gold, silver and copper futures and options in the week ended Jan. 24, as prices of the metals climbed, US Commodity Futures Trading Commission figures showed.

Copper slipped in moderate volume on Friday as US economic growth figures disappointed investors.

The US economy, the world's largest, grew at its fastest pace in 1-1/2 years in the fourth quarter, but a strong rebuilding of stocks by businesses and weak spending on capital goods hinted at slower growth in early 2012.