China\'s defence minister on Sunday denied that Beijing was behind Internet attacks on foreign targets and echoed US-British calls for international talks to toughen up cyber-security. \"It is hard to attribute the real source of attacks and we need to work together to make sure that this security problem won\'t be a problem,\" Defence Minister Liang Guanglie told a security forum in Singapore. \"Actually in China we have also suffered quite a wide range and frequency of cyber-attacks,\" he said. \"The Chinese government attaches importance also to cyber-security and stands firmly against all kinds of cyber-crimes,\" he said. China has been accused by the United States, Canada and other nations of spearheading online attacks on government agencies as well as companies, although the Beijing government has always denied this. Last week, Internet giant Google said a cyber-spying campaign originating in China had targeted Gmail accounts of senior US officials, military personnel, journalists and Chinese political activists. The United States said Friday it had highlighted Google\'s concerns with Beijing, but the Chinese government has described any suggestion that it was behind the attack as \"unacceptable\". Chinese hackers have also been accused of attacking sites critical of Beijing, with a US lawmaker in April urging Washington to protect a popular activist site after it was hit by hackers apparently upset at a petition to free detained artist Ai Weiwei. \"It is important for everyone to obey or follow laws and regulations in terms of cyber-security,\" said Liang, who joined calls for global coordination to deal with the issue. Addressing the same forum in Singapore, the United States and Britain appealed Saturday for international cooperation against online threats following a fresh spate of attacks on government and corporate targets. US Defense Secretary Robert Gates and British Defence Secretary Liam Fox underscored the urgency of the problem but avoided singling out Beijing as being the source of cyber-attacks. \"I think that one of the things that would be beneficial would be for there to be a more open dialogue among countries about cyber (threats) and establishing some rules of the road,\" Gates said. Fox said Britain would host an international conference on what he called the \"war of the invisible enemy\" later this year. The talks in London will include discussions on a potential legal framework, he said. Earlier Sunday, Japanese videogame maker Nintendo reported that a website operated by its US subsidiary was hacked several weeks ago, with no personal information stolen. Besieged games rival Sony is already grappling to contain the fallout from a series of cyber-attacks that have compromised the personal details of millions of online users in one of the biggest data breaches ever. US aerospace giant Boeing said Friday on the sidelines of the Singapore conference that it was under \"continuous\" cyber-attack but that there had been no breach of its databases.