In the final weeks of Muammar Gaddafi's regime, Chinese arms companies offered to sell around $200m (£124m) worth of weaponry to Muammar Gaddafi's government in breach of a UN arms embargo, according to documents found in Tripoli.
The Chinese foreign ministry has confirmed that Libyan officials travelled to Beijing to buy arms in July, although it said no contracts were signed and no weapons delivered.
A spokeswoman said the Chinese government had not known of the state-owned firms' meetings.
According to the documents, obtained by Canada's Globe and Mail newspaper, the Chinese firms offered to sell rocket launchers, anti-tank missiles and other weapons.
The paper named the firms as the China North Industries Corporation (Norinco), China Precision Machinery Import-Export Company and China Xinxing Import and Export Company.
The companies either could not be contacted or said no one was available to comment.
It said the firms had suggested deals could be made via third countries such as Algeria or South Africa, both of which had said they supported the arms embargo.
Algeria's foreign minister, Mourad Medelci, said last week that the country had "resolutely applied" the terms of UN resolutions.
Omar Hariri, the chief of the rebels' military committee, told the newspaper he was "almost certain" that the guns arrived and were used against them, saying it explained how brand-new weaponry had reached the battlefield.
"We have hard evidence of deals going on between China and Gaddafi, and we have all the documents to prove it," a rebel military spokesman, Abdulrahman Busin, told the New York Times. He added that there was evidence of "at least ten" other governments or companies supplying arms to Gaddafi illegally.
The Globe and Mail reporter Graeme Smith said he found the documents, printed on the stationery of a government procurement department, in rubbish in a neighbourhood where many officials had lived.
"After the passing of resolution 1970 by the security council, we notified relevant government departments to strictly implement it," China's foreign ministry spokeswoman, Jiang Yu, told a daily news conference in Beijing.
"We have clarified with the relevant agencies that, in July, the Gaddafi government sent personnel to China without the knowledge of the Chinese government and who engaged in contact with a handful of people from the companies concerned.
"The Chinese companies did not sign arms trade contacts, and nor did they export military items to Libya.
"I believe that the agencies in charge of the arms trade will certainly treat this seriously."
In 2003, the US imposed sanctions on one of the firms involved, Norinco, alleging that it had sold missile-related parts to Iran. The firm said the accusations were "groundless and unjustified".
The China Xinxing Import and Export Company was set up in 1984 under the People's Liberation Army and has struck deals with more than 100 countries, according to its website.
The news comes at an extremely delicate time for Beijing, which has sought to improve relations with the Libyan rebels. Last month, an official with a rebel oil firm suggested they might freeze out countries that had not supported them.
China – which, as a permanent member of the UN security council, has veto power – surprised many by backing the arms ban in February and abstaining on the vote on Nato air strikes.
But it later condemned the bombing and has not formally recognised the National Transitional Council (NTC) as the legitimate authority in Libya, although it has held talks with rebels and said it values the NTC's "important role".
China is the third-largest importer of Libyan crude oil, and a foreign ministry spokesman, Ma Zhaoxu, said last week that it was "ready to maintain close contact" with the NTC.
But at the weekend, Mustafa Abdul Jalil, the head of the NTC, complained that China had obstructed the release of some of Libya's frozen assets.
China had agreed $15bn of Libyan assets held overseas should be unfrozen, but a rebel spokesman said it had opposed handing control of more to the interim ruling council.
