EDEN PRAIRIE, Minn. (AP) — UnitedHealth Group said last week it was under a Department of Justice investigation.

The company said it has started complying with both criminal and civil requests from federal investigators and it was cooperating with them.

“(UnitedHealth) has a long record of responsible conduct and effective compliance,” the company said in a Securities and Exchange Commission filing.

Earlier this year, The Wall Street Journal said federal officials had launched a civil fraud investigation into how the company records diagnoses that lead to extra payments for its Medicare Advantage, or MA, plans. Those are privately run versions of the government’s Medicare coverage program mostly for people ages 65 and over.

The company’s UnitedHealthcare business covers more than 8 million people as the nation’s largest provider of Medicare Advantage plans. The business has been under pressure in recent quarters due to rising care use and rate cuts.

UnitedHealth Group Inc. said in February that it wasn’t aware of the start of any new activity as the paper reported.

The company said last week that it reached out to the Justice Department “after reviewing media reports about investigations into certain aspects of the company’s participation in the Medicare program.”