This photograph taken on March 5, 2021 shows the flag of the World Health Organization (WHO) at their headquarters in Geneva amid the Covid-19 coronavirus outbreak. (Photo: AFP)

The Covid-19 pandemic is in a critical phase, the World Health Organization said Monday, warning cases were surging despite proven measures to rein in the spread.

"We are in a critical point of the pandemic right now," Maria Van Kerkhove, the WHO's technical lead on Covid-19, told reporters.

"The trajectory of this pandemic is growing. It is growing exponentially. This is not the situation we want to be in 16 months into a pandemic, when we have proven control measures," she said.