WASHINGTON, Oct. 4 (Xinhua) -- The pace of rent growth in U.S. office buildings slowed in the third quarter, and leasing was sluggish as companies tapped the brakes on expansion due to credit-market turmoil and uncertainty about the economy's direction, The Wall Street Journal reported Thursday.

    Although rent growth remained healthy in the third quarter, up 2.4 percent to 24.17 U.S. dollars per square foot from 23.61 dollars in the second quarter, it was off the pace set in the first six months of the year, when rents grew an average 3 percent per quarter.

    The report was quoting a survey of 79 of the top U.S. office markets by Reis Inc., a New York-based commercial real-estate research firm.

    That, combined with sluggish growth in office-based employment over the last several months, raises concern about the direction of the market at a critical time for real-estate investors, though it is too early to tell if it is a one-quarter blip or something worse, says Sam Chandan, chief economist for Reis.

    For now, the three-and-a-half year old office recovery is still under way, if showing signs of weakness.

    The vacancy rate hit its lowest level in six years, dropping to12.5 percent in the third quarter from 12.7 percent in the second quarter, though the pace of absorption -- the change in the total amount of space leased nationwide -- slowed.

    Absorption totaled 14.8 million square feet in the third quarter compared to 17.3 million in the second.

    "There is a slowdown," said Barry M. Gosin, chief executive of Newmark Knight Frank, a New York-based commercial real-estate service firm. "Any major financial institution is not in a hurry to rent space right at the moment."