The U.S. report on its probe into a shipment last month of banned bovine material and measures to prevent a recurrence is "insufficient," farm minister Shoichi Nakagawa said Monday, adding that Japan plans to raise a range of questions with Washington.

It will thus be several days before Tokyo finalizes its response to the report, in which the U.S. Department of Agriculture admitted to a flaw in the inspection system for beef exports to Japan and vowed to take various measures to prevent a repeat of the incident, Nakagawa said.

He spoke on Japan's initial response to the report after visiting Prime Minister Junichiro Koizumi at his office to brief him on the contents of the U.S. effort.