China called on the World Health Organization Thursday to take a "just" position on COVID-19, after the body criticized Beijing's "very narrow" definition of virus deaths.

WHO emergencies director Michael Ryan had told reporters Wednesday that official statistics were not showing the true impact of the outbreak in China, where cases have surged in the wake of Beijing's decision last month to suddenly lift years of stringent virus controls.

Beijing hit back Thursday, insisting China "maintained close cooperation with the WHO" and that it had "always shared relevant information and data with the international community, with an open and transparent attitude."

"We... hope the WHO secretariat will uphold a scientific, objective and just position, and make efforts to play a positive role for the world's response to the pandemic challenge," foreign ministry spokeswoman Mao Ning told a press briefing.

"According to an incomplete tally, there have been over 60 technical exchanges between the two sides since Covid-19 was first reported, on topics including Covid-19 prevention and control, treatment, vaccine R&D, and virus origin tracing," she added.

China has only recorded 23 COVID deaths since December and has dramatically narrowed the criteria for classifying fatalities -- meaning Beijing's statistics on the unprecedented wave are now widely seen as not reflecting reality.

Over a dozen countries have imposed mandatory COVID tests for visitors from China -- a move Beijing has decried as "unacceptable."