BEIJING -- Chinese authorities lifted quarantine in three more areas hit by African swine fever, as prevention and control measures have put outbreaks under control.

Laboratory tests and on-site assessments by local authorities show that the epidemic has been eliminated in the counties of Taoyuan and Yuanling in central Hunan Province and Taiyuan, northern Shanxi Province, the Ministry of Agriculture and Rural Affairs said Tuesday on its website.

No new cases have been reported at the three infected areas over the past six weeks, with immediate actions having been taken to block, cull and disinfect affected pigs after the outbreak.

The ministry has demanded local governments to step up monitoring of pigs and take proactive measures to prevent recurrence of the disease.

At least 631,000 pigs have been culled across the country since the outbreak as early as the end of September, while measures including strengthened monitoring of live pig transportation and tightened entry inspection and quarantine have been taken.

Thanks to these efforts, the situation has started to improve and restrictions have been lifted in about 38 affected areas.

African swine fever is believed to only infect pigs. No humans or other species have been infected.