The European Commission has published what it calls a 'roadmap' to bring all of Europe out of the COVID-19 crisis together.
The commission has published three principles - namely that action must be based on science and have public health at its centre, while balancing social and economic remedies.
It says action must be coordinated between the member states to avoid negative spillover effects.
The commission noted that "we are still in firefighting mode", but that measures taken by member states are working.
"However, these measures and the corresponding uncertainty come at a dramatic cost to people, society and the economy, and cannot last indefinitely", it says.
European Commission President Ursula von der Leyen says: "Saving lives and protecting Europeans from the coronavirus is our number one priority.
"At the same time, it is time to look ahead and to focus on protecting livelihoods.
"Even though conditions in the member states still vary widely, all Europeans rightly ask themselves when and in what order the confinement measures can be lifted.
"Responsible planning on the ground, wisely balancing the interests of protection of public health with those of the functioning of our societies, needs a solid foundation.
"That's why the commission has drawn up a catalogue of guidelines, criteria and measures that provide a basis for thoughtful action.
"The strength of Europe lies in its social and economic balance. Together we learn from each other and help our European Union out of this crisis."
The plan notes that any relaxing of restrictions should be based on several criteria.
This includes epidemiological criteria, showing that the spread of the disease has significantly decreased, and that there is sufficient health system capacity - for example taking into account the number of people in intensive care units.
It says there also has to be appropriate monitoring capacity, including large-scale testing capacity to quickly detect and isolate infected individuals - as well as tracking and tracing.
While at a minimum, member states should notify each other and the commission before they lift measures.
It also says that coordination between member states must be used to avoid negative effects, adding: "This is a matter of common European interest."
Phasing out of restrictions
The plan also covers the phasing-out of restrictions.
It says this must include gathering harmonised data and developing a robust system of reporting and contact tracing, expanding testing capacity and increasing the capacity and resilience of national health care systems.
The commission - in consultation with the European Centre for Disease Prevention and Control (ECDC) - has adopted guidelines on different coronavirus tests and their performance.
The roadmap also has recommendations member states should consider when planning to lift measures.
These include measures being lifted gradually in different steps, internal border controls being lifted in a coordinated manner and a phasing-in of economic activity.
It says: "There are several models that can be implemented, e.g. jobs suitable for teleworking, economic importance, shifts of workers, etc.
"The entire population should not return to the workplace at the same time.
"Gatherings of people should be progressively permitted, taking into account the specificities of different categories of activity".
While it adds that efforts to prevent the spread of the virus should be sustained, with awareness campaigns to encourage the population to keep up the strong hygiene practices and social distancing.