The number of Americans filing for unemployment benefits unexpectedly rose last week, but remained below levels associated with a healthy labor market.

Initial claims for state unemployment benefits increased 7,000 to a seasonally adjusted 284,000 for the week ended Jan. 9, the Labor Department said on Thursday. The prior week's claims were unrevised.

Still, it was the 45th consecutive week that claims remained below the 300,000 mark, which is associated with strong labor market conditions. That is the longest such stretch since the early 1970s.

Economists polled by Reuters had forecast claims slipping to 275,000 in the latest week. The increase likely reflects volatility rather than a change in labor market conditions, as the data is difficult to adjust during holidays. Claims also tend to increase at the start of each quarter.

A Labor Department analyst said there were no special factors influencing the data and only claims for Puerto Rico had been estimated. The four-week moving average of claims, considered a better measure of labor market trends as it strips out week-to-week volatility, rose 3,000 to 278,750 last week.

The labor market has largely shrugged off weakness in the economy, with nonfarm payrolls surging in December. Economic growth has been hit by a strong dollar, slowing global demand, efforts by businesses to slim an inventory bloat, and spending cuts by energy companies.

The claims report showed the number of people still receiving benefits after an initial week of aid rose 29,000to 2.26 million in the week ended Jan. 2. The four-week moving average of the so-called continuing claims increased 5,250 to 2.22 million. 

By Lucia Mutikani - Reuters (Editing by Paul Simao)