The number of Americans filing for unemployment benefits rose more than expected last week, but the underlying trend remained consistent with healthy labor market conditions.

Initial claims for state unemployment benefits increased 13,000 to a seasonally adjusted 277,000 for the week ended June 11, the Labor Department said on Thursday. Claims for the prior week were unrevised.

Economists polled by Reuters had forecast initial claims rising to 270,000 in the latest week. Claims have now been below 300,000, a threshold associated with a strong job market, for 67 straight weeks, the longest streak since 1973.

The four-week moving average of claims, considered a better measure of labor market trends as it irons out week-to-week volatility, slipped 250 to 269,250 last week.

A Labor Department analyst said there were no special factors influencing last week's claims data and no states had been estimated.

The claims report comes a day after the Federal Reserve downgraded its assessment of the labor market, saying "the pace of improvement in the labor market has slowed while growth in economic activity appears to have picked up."

The U.S. central bank, which kept interest rates unchanged, also noted that while the unemployment rate had declined, "job gains have diminished."

But with job openings near record highs, both economists and Fed officials expect job growth to pick up after the economy added only 38,000 jobs in May, the smallest increase since September 2010. The Fed lifted its benchmark overnight interest rate in December for the first time in nearly a decade.

Thursday's claims report showed the number of people still receiving benefits after an initial week of aid rose 45,000 to 2.16 million in the week ended June 4. The four-week average of the so-called continuing claims gained 1,000 to 2.15 million.