The Pennsylvania Department of Revenue is launching a pilot program to intensify its examination of sales and use tax returns, the agency said Tuesday.

The new unit in Harrisburg will conduct what the revenue department called "remote examinations" of business activities by comparing information reported to the state with other sources, such as the IRS, other state agencies, and third parties.

If discrepencies are found, the department will send letters asking for an explanation, it said.

Businesses that have not registered for a sales tax license could be asked to fill out a questionnaire to see if they should be collecting sales tax.

The department of revenue did not respond to a request for more information, such as how many people work for the new unit.

The state collected $9.5 billion in sales tax in fiscal 2015. It was the state's second-biggest source of tax revenue behind personal income tax.