SEATTLE (AP) — Two members of a family that owns an engine company in Washington state pleaded guilty Tuesday to federal charges of knowingly hiring undocumented workers.

The case stems from an immigration raid in February on Yamato Engine Specialists of Bellingham — the first such action after President Barack Obama took office calling for stepped up efforts to prosecute the companies that hire undocumented workers.

Shirin Dhanani Makalai, 52, and her brother Shafique Dhanani, 46, entered guilty pleas in U.S. District Court, admitting they allowed undocumented workers to file false employment forms with the government. Under the plea agreement, the two most likely face probation.

Federal prosecutors have also charged the company with conspiring to encourage undocumented immigrants to remain in the United States between 2006 and 2009. A court hearing on the charge was delayed. The company faces a maximum fine of $500,000.

"Today's guilty pleas demonstrate the commitment of ICE special agents to investigating leads, uncovering the facts, and holding criminal employers accountable," said John Morton, assistant secretary of homeland security for U.S. Immigration and Customs Enforcement in a statement.

The two sat solemnly through the court proceedings. Their family — which left Uganda decades ago, and moved to Bellingham about 20 years ago and opened a manufacturing plant.

"We very much regret violating the law and dishonoring the fine reputation Yamato Engines and our family enjoys (in) the Whatcom County community," the defendants said in a statement.

The family said that going forward they will make sure all employees at Yamato will follow all legal requirements.

According to court documents, Shafique Dhanani admitted knowingly accepting false documents from a worker. His sister pleaded guilty to a similar situation.

The February raid, which led to the arrests of 28 workers, shook immigrant advocates and prompted Homeland Security Secretary Janet Napolitano to order a review of the actions leading up to it. On Tuesday, Homeland Security spokesman Matt Chandler said the results of the review will not be made public.

Following the raid, nearly all of those arrested were given work permits which will continue in effect as long as the government continues its investigation of Yamato.

Tuesday's ruling didn't please activists on either side of the immigration issue.

OneAmerica, a Seattle-based immigrant advocate organization, said in a statement that going after employers does not address immigration reform.

Ira Mehlman, a spokesman for the Federation for American Immigration Reform, which seesk stricter rules, said that sentencing employers that break immigration laws to probation won't provide much deterrence.

U.S. Attorney Jeff Sullivan said the guilty pleas represent the first successful prosecution in Western Washington of an employer knowingly hiring undocumented workers.

"This case should put employers on notice that if they knowingly employ those who lack legal status, they face prosecution for federal felonies," Sullivan said.