The World Health Organization has set up an independent panel to review its handling of the Covid-19 pandemic and to check responses by governments.
The move follows strong criticism by Donald Trump's US administration, which accused the WHO of being "China-centric."
And the United States have now given formal notice it will be leaving the UN agency after 12 months.
Former New Zealand prime minister Helen Clark and former Liberian president Ellen Johnson Sirleaf will head the panel and choose its members, WHO director-general Tedros Adhanom Ghebreyesus told a virtual meeting with representatives of its 194 member states.
And there would be an interim report to an annual meeting of health ministers being reconvened in November. Clark said the assignment "could only be described as exceptionally challenging."
Tedros also noted that in May the WHO's member states adopted a resolution put forward by the European Union calling for an "impartial, independent and comprehensive evaluation" of the global response to the pandemic.
And reacting to Washington commencing its withdrawal from the organization, Tedros said a divided world could not conquer the coronavirus challenge.
He added: "Together is the solution unless we want to give the advantage to the enemy, to the virus that has taken the world hostage."
More than 12 million people have now been reported to have been infected by the novel coronavirus and at least 548,400 have died.