China tried to block a UN report alleging that Chinese ammunition was sent to Darfur in violation of a UN arms embargo but apparently didn't succeed, UN diplomats said yesterday.

The UN security council committee monitoring sanctions against Sudan met yesterday afternoon and two diplomats familiar with the closed-door deliberations said China argued that the report by the committee's panel of experts should not be sent to the council. One diplomat said China claimed the panel was unprofessional and flawed, and challenged its methodology.

The diplomats said the committee chairman, Austria's UN ambassador Thomas Mayr-Harting, agreed that the annex to the report would be updated with a letter to include additional information on sources. But they said the report itself would not be changed, and will likely be formally sent to the council next week.

Diplomats at the meeting said China got no support from the other committee members, who include representatives from all 15 council nations.

According to the diplomats, the draft report said Chinese shell casings were found after attacks against the joint UN-African Union peacekeeping force in Darfur. Markings showed the ammunition had been manufactured after 2009, the diplomats said, speaking on condition of anonymity because the report has not been published.

The security council initially imposed an arms embargo on rebels and the government-allied Janjaweed militias in Darfur. In March 2005, it extended the embargo to include Sudan's government.

The Darfur conflict began in February 2003 when ethnic African rebels took up arms against the Arab-dominated Sudanese government in Khartoum, claiming discrimination and neglect. Khartoum is accused of retaliating by arming local nomadic Arab tribes and unleashing the Janjaweed on civilian populations – a charge the government denies.

UN officials say at least 300,000 people have lost their lives from violence, disease and displacement, and 2.7 million have been driven from their homes.

The UN panel of experts reported last November that the Sudanese government and rebel groups in Darfur were refusing to abandon the military option and increasingly violating the arms embargo.

China has been a key force in developing Sudan's vital oil sector and buying the country's crude oil and has close political ties to the government. Its alleged involvement in supplying ammunition, in violation of UN sanctions, was first reported by Foreign Policy magazine's Turtle Bay blog.

According to the two UN diplomats, the latest report by the panel of experts was first presented to the sanctions committee on 4 October.

The panel alleged that more than a dozen types of Chinese ammunition were used by Sudanese government forces in combat with rebels in Darfur over the past two years, the diplomats said.