The head of the World Health Organization (WHO) has urged unity, as the agency comes under continued fire from US President Donald Trump. Speaking on Wednesday, Director-General Tedros Adhanom Ghebreyesus defended the WHO's work and called for an end to the politicisation of Covid-19. The Ethiopian also said that he had received deaths threats and has been subjected to racist abuse. Mr Trump said he would consider ending US funding for the UN agency. He accused the WHO of being "very China-centric" and said they "really blew" their pandemic response. Dr Tedros has now dismissed the comments, insisting: "We are close to every nation, we are colour-blind." After first attacking the WHO the previous day, President Trump renewed his criticism at his news briefing on Wednesday, saying the organisation must "get its priorities right". He said the US would conduct a study to decide whether it would continue paying contributions, Also answering questions at the briefing on Wednesday, US Secretary of State Mike Pompeo said the administration was "re-evaluating our funding" of the WHO, adding; "Organisations have to work. They have to deliver the outcomes for which they were intended". Covid-19 first emerged last December in the Chinese city of Wuhan, which has just ended an 11-week lockdown. An advisor to the WHO chief earlier said their close work with China had been "absolutely essential" in understanding the disease in its early stages. Mr Trump's attacks on the WHO come in the context of criticism of his own administration's handling of the pandemic, especially early problems with testing. The WHO approved a coronavirus test in January - but the US decided against using it, developing its own test instead. However, in February, when the testing kits were despatched, some of them didn't work properly and led to inconclusive results. Public health experts say the delay enabled the virus to spread further within the US.