U.S. health regulators are investigating hundreds of reported complications with dozens of recalled children's medications made by Johnson & Johnson, including 30 deaths, but so far no direct link has been found, according to a congressional report.

The Food and Drug Administration does not consider the 775 reported adverse events a "spike" and there is no "clear pattern" indicating the problems were caused by the recalled products, Democratic staff on the House Oversight and Government Reform Committee said in a document released on Tuesday.

"At this time, FDA is not aware of any child being harmed by taking one of the recalled products," said the staff report, dated May 24. "FDA is still investigating some of these adverse events to determine if the events were related to a child taking one of the recalled medicines."

Since the April 30 recall, several hundred more cases of complications, including seven deaths, have been reported to the FDA, the report said.

When the recall was announced, FDA officials said the chance of getting sick from the products was "remote."

On Thursday, the committee will hold a hearing with officials from both the FDA and J&J over manufacturing lapses that led to contamination and a nationwide recall of liquid children's versions of Tylenol pain reliever and other medications.

Infant and children's versions of pain medicine Motrin and allergy drugs Benadryl and Zyrtec were also recalled. In total, about "70 percent of the market for over-the-counter pediatric liquid medicines were involved," the staff said.

"It is the largest recall of children's medicine in the history of the FDA," they wrote in the memo to committee lawmakers.

In a separate document from committee Republicans, staff questioned the corporate culture at J&J, a diversified consumer healthcare company, and increased autonomy at its subsidiaries.

"Minority staff believes that there have been ongoing, systemic failures at McNeil facilities which have put children's health at risk," the Republican staff wrote.

J&J has shut down manufacturing of the liquid nonprescription medicines made at its Fort Washington, Pennsylvania, plant until it can win clearance from the FDA to resume production.

Agency inspectors found multiple problems, including bacterial contamination of ingredients and filthy equipment, among other quality lapses. They also found that the products made by J&J's McNeil Consumer Healthcare unit "had the potential to be super potent," the report said.

The head of the U.S. Senate health committee is also investigating the recall, but so far no hearing is planned, a spokeswoman for Committee Chairman Senator Tom Harkin has said.