A private survey shows U.S. businesses sharply increased hiring in December, helped by a surge of new construction jobs to help rebuild from Superstorm Sandy.

Payroll processor ADP said Thursday that employers added 215,000 jobs in December. That's more than November's total of 148,000, which was revised higher.

The survey showed companies added 39,000 construction jobs last month. That was partly in response to the storm but also an indication of the housing recovery under way.

The increase in hiring took place before Congress and President Barack Obama reached a deal to avert sharp tax increases from hitting most Americans. That suggests the uncertainty surrounding the fiscal cliff did little to slow the job market.

"The job market held firm in December despite the intensifying fiscal cliff negotiations," said Mark Zandi, chief economist at Moody's Analytics, which is working with ADP to create the employment report. "Businesses even became somewhat more aggressive in their hiring at year end."

The ADP survey covers hiring only in the private sector. ADP's figures have diverged at times from the government's more comprehensive jobs report, which will be released Friday. Most economists predict that report will show employers added roughly 150,000 jobs last month.

Even with the strong month of job growth, the ADP survey offered a reminder of a key area of the economy remains weak: Manufacturers cut 11,000 jobs.

And Congress approved a budget deal this week that delayed crucial decisions about spending cuts for another two months. That assures more confrontation and uncertainty, especially because Congress must reach agreement later this winter to raise the government's debt limit.