BEIJING?-?Three major websites in China voiced their resolution Tuesday to contain online rumors in response to a warning proposal meted out Monday.

Chiefs of sina.com, baidu.com and qq.com promised the government that they will firmly cooperate with relevant departments to crack down on the online spreading of rumors, saying they will improve self-management and take effective measures toward this goal.

The Internet Society of China released a written proposal Monday calling on Internet companies and websites to strengthen self-discipline and prevent the spread of online rumors.

Microblogging websites should not be a hotbed for spreading of rumors, said an unidentified chief of sina.com, which operates the country's most popular microblogging site Weibo.com. He said Sina is improving measures to control the release of contents on Weibo.com and boost capacity for finding out and removing rumors posted on it.

Weibo.com and another major Chinese microblogging site t.qq.com, suspended comment functions from March 31 to April 3 after they were punished for allowing rumors to spread.

The move had widespread support from users and Sina will continue to lead users participate in rumor clarification, said the chief.

A chief from Baidu.com, also unidentified, said it was deleting illegal and fake information in its search results and it would further increase technical and manpower investment to banish disinformation.

The website qq.com is learning from the past experience and improving the safety strategy for its microblogging service so as to further curb the spreading of online rumors through microblogging sites, said an unnamed chief from qq.com.