Private-sector employment rose less than expected in June, underscoring concerns about a weak labor market, while U.S. Midwest business activity grew slightly more than expected.

U.S. private employers added a paltry 13,000 jobs in June, compared with a revised gain of 57,000 in May, a report by a payrolls processor showed on Wednesday. Economists had forecast a rise of 60,000 jobs, according to a Reuters survey.

Separately, the Institute for Supply Management-Chicago business barometer fell to 59.1 in June from 59.7 in May, and economists had forecast a June reading of 59.0. A reading above 50 indicates expansion in the regional economy.

The private sector job figures added to worries about a slowing labor market recovery ahead of Friday's widely watched U.S. government payrolls and unemployment report.

"The data is quite concerning. If this weaker trend in private sector employment is confirmed on Friday, it would increase the risk of weak growth in the second half of 2010," said Zach Pandl, economist at Nomura Securities International in New York.

U.S. stocks opened lower after the ADP data then recovered some ground to trade higher after the Midwest business activity data.

The U.S. dollar pared gains against the yen on concerns about the outlook for the economy, while U.S. Treasury debt prices mostly eased.

Friday's U.S. Labor Department jobs report is expected to show a fall in overall non-farm payrolls of 110,000 in June overall, as temporary workers hired to conduct the U.S. census were laid off, but a gain in private payrolls of 112,000, according to a Reuters poll of analysts.

Another report Tuesday showed business activity in New York City dipped in June from record levels in May, although a gauge of job growth rose.

The Institute for Supply Management-New York's seasonally adjusted index of current business conditions fell to 69.3 in June from 89.9 in May.

In other data Wednesday, refinancing drove total U.S. mortgage applications to an eight-month peak, as loan rates fell to or near record lows, but demand to buy homes sank toward 13-year lows last week, the Mortgage Bankers Association said.

The U.S. housing market continued to deflate after a spring sales spree, fueled by now-expired federal tax credits of up to $8,000, robbed from summer home buying.

The upside is now limited by unemployment stuck near 10 percent, heavy foreclosure supply and pent-up selling from owners just waiting for the right time to put their homes back on the market.

Mortgage refinancing requests jumped 12.6 percent in the week ended June 25 to the highest level since May 2009, as average 30-year mortgage rates slid 0.08 percentage point to 4.67 percent, the industry group said.

The 30-year loan rate flirted with the record low of 4.61 percent set in March 2009, according to the MBA's records dating back to 1990, while the 4.06 percent 15-year rate was an all-time lows.

Refinancing drove total mortgage applications up by 8.8 percent, seasonally adjusted, last week. Nearly 77 percent of all loan requests were for a refinancing, the highest share since April 2009.

Despite low borrowing costs and home prices average about 30 percent less than their peaks four years ago, applications to buy homes dropped 3.3 percent to hover just above 13-year lows.