The Kansas City Star reported Sunday that the checks, based on federal income tax returns the IRS processed before April 15, went out Friday.

IRS workers had printed and mailed about 105 million checks before the July Fourth holiday. A total of 130 million stimulus checks are expected to be sent to taxpayers.

The IRS still has to process the tax returns that it did not get processed by April 15, as well as returns from taxpayers who requested automatic 6-month extensions in April to get more time to finish their returns.

Households getting paper checks should see those six to eight weeks after their returns are processed, the newspaper said.

All the stimulus checks must be cut by Dec. 31, said Michael Devine, an IRS spokesman in St. Louis.

"The law says that the payments must all be made this year," he said.