At least two doctors in Syria's opposition-held northwest have been infected with the coronavirus, according to a monitoring group Saturday, raising the total number of cases in the overcrowded rebel enclave to three.

The Syrian opposition and militant groups control the Idlib area, which is home to more than 3 million people, most of them displaced by the war and living in tent camps and overcrowded facilities. Local health facilities have been targeted in Syrian government attacks that have recently displaced nearly a further million people.

The World Health Organization has urged countries grappling with coronavirus to step up control measures, saying it is still possible to rein it in, as some nations clamp fresh restrictions on citizens.

With case numbers worldwide more than doubling in the past six weeks, Uzbekistan on Friday returned to lockdown and Hong Kong said schools would close from Monday after the city recorded "exponential growth" in locally transmitted infections.

The World Health Organization said Friday that it is still possible to bring coronavirus outbreaks under control, even though case numbers have more than doubled in the past six weeks.

Bolivia's interim president became the latest world leader to test positive for the coronavirus Thursday, as the United States notched yet another record-breaking surge of cases while global infections and fatalities continued their relentless rise.

Brazilian President Jair Bolsonaro, who has tested positive for COVID-19, said on Facebook Thursday that he was "very well" and again advocated the use of the controversial drug hydroxychloroquine. 

Iran reported a new single-day record death toll of 221 from the novel coronavirus on Thursday, after weeks of rising numbers in the Middle East's worst-hit country.

Is it safe to visit the dentist during the COVID-19 pandemic?

Virus cases jump in worst-hit trio of US, Brazil and India

India on Thursday reported nearly 25,000 new coronavirus infections, as the disease continued its ominous spread through the nation of nearly 1.4 billion people.

Five million people in Australia's second-biggest city began a new lockdown Thursday, returning to tough restrictions just weeks after they ended as Melbourne grapples with a resurgence of coronavirus cases.

U.S. President Donald Trump has said he disagrees with the assessment of the country's top immunologist, Anthony Fauci, on the dire situation the United States faces as cases of the novel coronavirus continue to spread.