Copper and aluminum dropped to three-month lows in London and New York after manufacturing growth slowed in China, the largest industrial metals user, and worries over U.S. spending cuts rise.

On the London Metal Exchange three- month copper touched its lowest since November last year at $7,652 a tonne, and was $7,665 per tonne in official rings, down from a closing bid of $7,815 on Thursday. Prices fell more than 4% in February.

On the Comex in New York, Copper for delivery in May sank 2.1% to $3.4725 a pound, also the lowest price since Nov. 19. The commodity was down 2% at 7:50 a.m. E.T on Friday, which means the red metal price has already fallen 4.7% this year.

Trading was 79% higher than the average in the past 100 days for this time of day, according to data compiled by Bloomberg.

Because of copper's widespread applications in most sectors of the economy —from homes and factories, to electronics and power generation and transmission— demand for this key metal is often viewed as a reliable leading indicator of economic health.