The world has never been in a better position to end the Covid-19 pandemic, the head of the World Health Organisation said on Wednesday, urging nations to keep up their efforts against the virus that has killed over six million people.

"We are not there yet. But the end is in sight," WHO Director-General Tedros Adhanom Ghebreyesus told reporters at a virtual press conference.

The comment was the most optimistic from the UN agency since it declared Covid-19 an international emergency and started describing the virus as a pandemic in March 2020.

The virus, which emerged in China in late 2019, has killed nearly 6.5 million people and infected 606 million, roiling global economies and overwhelming healthcare systems.

The rollout of vaccines and therapies have helped to stem the severity of disease. Deaths from Covid-19 last week were the lowest since March 2020, the U.N. agency reported.

Still, countries need to take a hard look at their policies and strengthen them for Covid-19 and future viruses, Tedros said.

He also urged nations to vaccinate 100% of their high-risk groups and keep testing for the virus.

The WHO warned of the possibility of future waves of the virus and said countries need to maintain adequate supplies of medical equipment and healthcare workers.

"We expect there to be future waves of infections, potentially at different time points throughout the world caused by different subvariants of Omicron or even different variants of concern," said WHO's senior epidemiologist Maria Van Kerkhove.

Monkeypox cases, too, were on a downtrend but Tedros urged countries to keep up the fight.

WHO officials said last month that it is possible to eliminate the monkeypox outbreak in Europe by stepping up vaccination and testing.

"As with Covid-19, this is not the time to relax or let down our guard."