The government is planning a workplace crackdown on illegal immigrants after Congress failed to overhaul immigration laws, a Homeland Security Department spokesman said on Wednesday. The department will announce in the next several days the final version of a rule that would require employers to fire workers who falsify identity documents. Those that don't comply would face fines of up to $10,000. The rule, proposed last year, was delayed when Congress took up immigration reform, an attempt that failed in June despite heavy lobbying by the Bush administration.

The final rule will be announced within the next several days, Homeland Security Department spokesman Russ Knocke said.

"There are in fact going to be very tough consequences for those employers who chose to blatantly disregard the law," said Knocke, who declined to say how the final rule would differ from the initial proposal.

Employers are currently required to verify that their workers are in the United States legally by collecting their Social Security numbers and immigration documents.

Those numbers are checked against the U.S. government's database, and employers are notified of those that don't match up.

Up to 10 percent of the 250 million wage reports sent to the Social Security Administration each year don't match up, according to the Homeland Security Department, though many of those are due to record-keeping errors.

Under the proposed rule, employers would have to respond promptly when notified of a mismatch -- either by clearing up any clerical error or firing those found to be in the country illegally.

There are an estimated 12 million illegal immigrants living in the United States.