SEOUL (Reuters) - South Korean prosecutors searched offices at a Samsung Electronics Co Ltd 005930.KS unit on Friday as part of a probe into allegations the conglomerate had sabotaged workers' efforts to strengthen labor unions, the prosecutors' office said.

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The tech giant has often come under fire from politicians and civics groups for not engaging with organized labor and its existing unions tend to be small and weak.

The Seoul Central District Prosecutors office told reporters in a brief text message that it raided Samsung’s repair service unit outside Seoul.

“I think the administration is trying to put a brake on Samsung’s no-union policy, which labor has long criticized,” said Kim Tai-gi, an economics professor at Dankook University, referring to the labor-friendly government of President Moon Jae-in.

Samsung Group, the country’s top family-run business empire, has come under greater scrutiny since heir apparent Jay Y. Lee received a suspended jail term in February for bribing a former president.

“Samsung was already cornered in the wake of Jay Y. Lee’s case. It does not seem easy for Samsung to stick to the existing stance on unions,” Kim said.

During a bribery probe involving another former president earlier this year, investigators found thousands of documents suggesting the conglomerate had developed union-busting strategies, domestic media outlets reported.

A Samsung Electronics spokeswoman said the company was aware that prosecutors had secured labor-related documents. She declined to comment further on the probe and had no immediate comment on whether a raid had taken place at the unit which carries out repairs for Samsung Electronics products.

Prosecutors investigated similar accusations after a lawmaker disclosed a document in 2013 that she claimed contained Samsung’s guidelines on how to stop its employees from organizing unions.

However, the case was dropped as prosecutors could not verify the source of the document.