China is investigating several suspicious cases involving influenza-like symptoms but has not designated any probable or confirmed cases of swine flu, the World Health Organization said on Tuesday. 

Hans Troedsson, the WHO's China representative, gave no details of the suspicious cases, which the Chinese health ministry has not reported. 

"We are now confirming the situation," a health ministry spokesman told the German Press Agency dpa when asked about the report of suspicious flu cases. 

"We don't have any specific information now," the spokesman said. 

State media on Tuesday quoted Premier Wen Jiabao as saying at an emergency meeting of the State Council, China's cabinet, that the government must be "highly vigilant" against swine flu and report any cases promptly. 

"The Communist Party of China Central Committee and the government have paid great attention to the epidemic situation in countries such as Mexico, and the government has taken emergency measures to strengthen monitoring and prevention work," the State Council said in a statement after the meeting on Monday. 

The cabinet "did not exclude the possibility that the epidemic could spread to China" if the number of cases in other countries continued to expand, the official Xinhua news agency quoted the statement as saying. 

China's agriculture ministry and quality watchdog issued a joint notice on Monday suspending all imports of live pigs or products containing pork from Mexico and the US states of Texas, California and Kansas. 

In another emergency notice issued Sunday, the health ministry reassured the public that there is no evidence to suggest people can contract swine flu by eating pork. 

The government has asked people entering China from virus-hit countries to report any flu-like symptoms and ordered border inspectors to check the temperatures of incoming passengers. 

Temperature monitors were installed at most Chinese airports during the severe acute respiratory syndrome outbreak in 2003.