BRUSSELS (Reuters) - European Union countries must take care not to damage food and medicine supply lines as they slap on border restrictions in the drive to curb the spread of coronavirus, the EU’s executive arm said on Monday.

From Portugal in the west to economic powerhouse Germany to Hungary in the east, EU countries have tightened frontier controls across the normally open-border Schengen zone which includes most member states as well as non-members Switzerland and Norway.

“The coronavirus crisis has highlighted the challenge of protecting the health of the population whilst avoiding disruptions to the free movement of persons, and the delivery of goods and essential services across Europe,” the European Commission said in a note to the 27 member states.

“The implementation of... checks of persons and goods should be governed by the principle of solidarity between member states,” said the new border management guidelines, which the Commission circulated to national capitals on Monday and which were seen by Reuters.

Member states’ ambassadors to Brussels will discuss the matter when they meet in person at 1800 GMT. Most other policy discussions in the EU are now conducted by videoconference, including a call between European leaders scheduled for Tuesday on the health and ensuing economic crises.

With the official death toll in Italy now at nearly 1,300 cases and at about 300 in Spain, the Commission’s calls for unity and solidarity have been falling largely on deaf ears as each nation tries to fend for itself, and reports spread of cars and trucks getting stuck at what are normally invisible borders.

The Commission said suspending freedom of movement for people, goods and services - fundamental principles of the EU Single Market - risked exacerbating panic buying and aggravating the economic impact of the coronavirus.

“In order to avoid shortages and a worsening of the social and economic difficulties that all European countries are already experiencing, maintaining the functioning of the Single Market is key,” the Commission said.

For the EU’s external borders, the Commission health has recommended screening measures for incoming and outgoing travellers.

A French government source said the EU would announce moves to beef up its external borders later in the day.