The Lancet study found that both drugs could produce potentially serious side effects, particularly heart arrhythmia.
And neither drug helped patients hospitalised with COVID-19, according to the study, which looked at the records of 96,000 patients across hundreds of hospitals.
Mr Tedros said both drugs were generally safe for patients with autoimmune diseases or malaria.
WHO chief scientist Soumya Swaminathan told Monday’s briefing the Solidarity Trial had been looking only at the effects of hydroxychloroquine and not chloroquine.
The decision to suspend enrolment for trials using hydroxychloroquine was “a temporary measure”, she said.
The Covid-19 pandemic, which began late last year in China, has killed nearly 350,000 people worldwide and infected almost 5.5 million.
While there is still no approved treatment or vaccine, drastic measures that at one point saw half of humanity under lockdown have pushed down transmission rates in several countries.
As many nations begin to gradually lift restrictions, the WHO stressed the need to maintain physical distancing and to scale up efforts to test and detect cases.
“All countries need to remain on high alert,” WHO expert Maria Van Kerkhove said.
“The virus will take the opportunity to amplify if it can.”
WHO emergencies chief Michael Ryan warned against the idea that the pandemic might move in seasonal waves.
“Making an assumption that it is on a downward trajectory, and the next danger point is some time in October or November, I think that would be a dangerous assumption,” he said.