Diplomats at the United Nations say China is trying to block the publication of a report which alleges that Chinese ammunition has been sent to Sudan's Darfur region.
The report says this violates an international arms embargo.
According to several accounts, the report says a dozen varieties of bullet casings from China were found at the sites of attacks against UN peacekeepers in Darfur.
The BBC reports there is no evidence cited that the Chinese ammunition was directly sold to the Sudanese government, or if it was, that Beijing knew Khartoum might use it in Darfur.
However, China has raised strong objections to what it calls "a controversial matter".
The report also cites the discovery of two types of bullet casings which were manufactured in Israel.