The World Health Organization, or WHO, warned on Wednesday that the risk of returning to lockdown is very real if countries emerging from pandemic restrictions do not move extremely carefully.

More than 3.5 million cases of COVID-19 and almost a quarter of a million deaths have been reported to the WHO. And since the beginning of April, an average of around 80,000 new cases have been reported every day.

"The risk of returning to lockdown remains very real if countries do not manage the transition extremely carefully, and in a phased approach," WHO Director-General Tedros Adhanom Ghebreyesus told a virtual news conference from Geneva.

He reiterated the WHO's criteria for when countries ease lockdown measures.

According to the WHO, a country must have a strong surveillance system, cases must be declining and transmission be controlled. Its health system capacities must be in place to detect, isolate, test and treat every case and trace every contact.

The country's outbreak risks must be minimized in special settings such as health facilities and nursing homes, and preventive measures must be in place in workplaces, schools and other locations where it's essential for people to go.

The WHO also emphasized that a country should be able to manage importation risks, and its communities be fully educated, engaged and empowered to adjust to the "new norm".

German Chancellor Angela Merkel announced on Wednesday further moves to lift lockdown restrictions, according to Politico.

While social distancing will continue until June 5, people will be allowed to meet in public with those from "one other household," Merkel said.

All shops are allowed to open, with a focus on hygiene and controlled access, avoiding queuing.

And Germany's soccer season is scheduled to resume "from the second half of May", Merkel said, with the top two professional leagues playing behind closed doors.

Belgium Prime Minister Sophie Wilmes said on Wednesday that visits to homes of family and close friends will be allowed in Belgium from Sunday, Mother's Day in Belgium.

She said such visits must be limited to four people and social distancing is still required.

Tedros noted on Wednesday that the COVID-19 pandemic has highlighted the importance of strong national and sub-national health systems as the foundation of global health security and universal health coverage.

He said strong and resilient health systems are the best defense not only against outbreaks and pandemics, but also against the multiple health threats that people around the world face every day.

"Prevention is not only better than cure, it's cheaper, and the smartest thing to do," he said.