NEW YORK (Reuters) - U.S. manufacturing lost some momentum in February as overseas demand declined, but output grew at its fastest pace in nearly a year, a survey showed on Friday.

Financial data firm Markit said its U.S. Manufacturing Purchasing Managers Index fell to 54.3 last month, nearly a full point below a preliminary estimate of 55.2. It stood at 55.8 in January.

A reading above 50 indicates expansion.

The pace of growth in new orders slowed, with the index slipping to 55.4 from 57.4 in January. Demand from abroad fell for the first time in four months.

"The slower order book growth largely reflects a renewed downturn in export orders, which could be in part attributable to a stronger than normal effect from the Chinese New Year holidays," said Chris Williamson, chief economist at Markit.

Output, however, rose smartly, with the subindex hitting 57.3, its best showing since March of 2012, suggesting, Williamson said, that "firms are expecting this slowdown to be temporary."

The manufacturing sector is expected to expand at a roughly 2 percent rate in the first quarter of the year, he said.

(Reporting By Steven C. Johnson; Editing by Chizu Nomiyama)