Lockdown restrictions should be lifted slowly and not "all at once" to avoid a resurgence of coronavirus, the World Health Organisation (WHO) has warned.
WHO director-general Dr Tedros Adhanom Ghebreyesus said stringent rules can only be relaxed if appropriate measures are in place.
Such measures include "significant" capacity for contact tracing, used to track infections and attempt to stop their spread, he said.
The warning came as Foreign Secretary Dominic Raab said the Government does not expect to make changes to the UK lockdown this week, three weeks after restrictions were imposed.
The Government has also repeatedly refused to reveal any details of its "exit strategy", despite continued questioning about how and when it might be implemented.
Speaking at a press conference on Monday, Dr Ghebreyesus said: "While Covid-19 accelerates very fast, it decelerates much more slowly.
"In other words, the way down is much slower than the way up.
"That means control measures must be lifted slowly, and with control.
"It cannot happen all at once."
The organisation said governments should consider six key factors before lifting the restrictions, including having systems in place to detect, test, isolate and treat every case of Covid-19.
Tracing every contact is also a key factor, it said.
Preventative measures must be taken in "essential" places such as work and schools, world leaders should ensure importation risks can be managed, and governments should ensure outbreak risks are minimised in settings such as health facilities and nursing homes, the WHO added.
Finally, there should be a commitment to help communities become "fully educated, engaged and empowered to adjust to the 'new norm"'.
Dr Ghebreyesus warned that countries must strike a delicate balance between measures which reduce Covid-19 deaths and other illnesses which can overwhelm health services.
"Our global connectedness means the risk of re-introduction and resurgence of the disease will continue," he added.
"Ultimately, the development and delivery of a safe and effective vaccine will be needed to fully interrupt transmission."
Dr Ghebreyesus also insisted stay-at home measures are only "part of the equation" and should "not be at the expense of human rights".
"There are many other basic public health measures that need to be in place," he said.
