The 2channel Internet bulletin board failed to delete most posts containing potentially illicit content, such as messages on buying or selling drugs, in the first half of this year, the National Police Agency said in a report Thursday.

Internet Hotline Center Japan, asked by the NPA to check items posted on the bulletin board, asked 2channel to delete 162 messages between January and June. The operator left 146, or 90.1 percent, of them untouched, the report says.

The center, which acts in response to reports from the general public, asked 2channel to delete 105 posts involving illicit sales of mobile phone handsets, 56 posts related to drugs and one involving the sale of a bank account.

The bulletin board deleted only 16, the NPA said.