It's the real Fortress Europe but not the way anyone expected.

EU leaders on Monday imposed a new wave of drastic measures aimed at slowing the spread of the coronavirus that has infected more than 180,000 people worldwide, killed more than 7,000 and is now threatening to overwhelm health systems in the richest, most-advanced countries on Earth.

"We are at war," French President Emmanuel Macron declared in a televised speech to his nation, in which he announced a 15-day lockdown that would permit only the most essential movements, beginning at noon on Tuesday.

"It is of course a sanitary war," Macron said. "We are not fighting against an army, or another nation. But the enemy is here. It is invisible, elusive and it is progressing. And this requires our general mobilization."

Macron's speech was just one of many remarkable public appearances on Monday by world leaders who rolled out unprecedented measures to fight the microscopic enemy.

German Chancellor Angela Merkel, appearing at a news conference in Berlin, said Germany would take "radical" steps including a ban on all travel "domestically or abroad" except for urgent work trips. She said bars, theaters, museums, cinemas and non-essential shops would be closed.

"These are measures that have never been seen before in our country," Merkel said, adding later: "We haven't seen a similar situation in the 70 years existence of the Federal Republic of Germany."

In Brussels, European Commission President Ursula von der Leyen and Council President Charles Michel announced that EU leaders would impose a 30-day travel ban on foreign visitors — a move aimed at sealing off all 27 EU nations as well as Iceland, Lichtenstein, Norway and Switzerland, which are part of the Schengen passport-free travel zone.

"We propose to introduce a temporary restriction on non-essential travel to the European Union," von der Leyen said at a news conference, "in order to not to spread the virus further, be it within the European Union or by leaving the European Union, but also to avoid non-essential travels, also not to have more potential strain on our health care system."

A senior Council official said that while the extraordinary travel ban would be "endorsed" by EU heads of state and government, legally it would be adopted and imposed by national governments. Von der Leyen said there would be some exemptions for goods traffic, health care workers, scientific experts and other emergency personnel.

"It looks as though we are now approaching the fast growth part of the upward curve and without drastic action, cases could double every five or six days" — Boris Johnson

Britain may no longer be part of the EU but it is facing similar challenges due to the pandemic. Prime Minister Boris Johnson warned the U.K. is fast approaching the peak of the coronavirus epidemic and asked everyone to stop non-essential contact and unnecessary travel.

"It looks as though we are now approaching the fast growth part of the upward curve and without drastic action, cases could double every five or six days," Johnson told a press conference.

Shortly after the new measures were announced, research by a team of scientists at Imperial College London, one of many groups advising government strategy on the disease, indicated that more than 250,000 people could die if the U.K. did not step up its containment measures.

Capitals make moves

On the Continent, even as the EU moved to ban travelers from third countries, airlines reeled from the near-total collapse of their industry, with Air France-KLM announcing it would cut 70 to 90 percent of its flights for the next two months, SAS Scandinavian suspending 90 percent of its operations, and an array of major carriers including Lufthansa and Alitalia turning to their home governments for giant emergency bailouts.

In Italy, the EU country with the most infections and deaths, Prime Minister Giuseppe Conte on Monday announced the approval of a €25 billion economic rescue package, including emergency aid for national and local businesses. Italian officials also said that they were racing to build a pop-up hospital for 500 patients in critical condition. The goal is to build the facility, in Milan’s fairgrounds area, in just 10 days.

“Nobody should feel abandoned,” Conte said in a speech. “The state is there.”

In Spain, the second hardest-hit EU country, which is already in a state of alarm, officials on Monday announced they would postpone upcoming elections in two northern regions, the Basque Country and Galicia. Spain and neighboring Portugal also announced their own partial border closures. And, in a sign that politics continues even in a pandemic, Prime Minister Pedro Sánchez urged a leadership role in fighting coronavirus for the G20 — the wider group of economic powers of which Spain happens to be a member. Sánchez said he had spoken to Crown Prince Mohammad bin Salman of Saudi Arabia, which currently chairs the G20, about holding an emergency summit.

An array of countries also declared new states of emergency on Monday, including Finland, Romania and Switzerland.

In the Netherlands, Prime Minister Mark Rutte on Monday became the first Dutch leader since 1973 to deliver an emergency address to the entire nation. “Many people have the feeling that we are on a roller coaster, which is going to ride faster and faster," Rutte said, adding that measures to the fight the coronavirus pandemic were "unprecedented for countries in peacetime." He said the Netherlands would for now avoid the more drastic lockdown approach in other EU nations, but would work to bolster the health care system and to prop up struggling businesses.

In Belgium, King Philippe also gave a rare speech, telling his nation: “The current situation reminds us of our vulnerability, but at the same time it brings out our strength."

But even if the worst is avoided, by slowing the virus and limiting deaths, the response looks certain to decimate the global economy.

Leaders of the G7, the world's most advanced economic powers, held an extraordinary meeting by videoconference on Monday, and pledged expanded international cooperation to fight the pandemic and stabilize world financial systems.

"We express our conviction that current challenges related to the COVID-19 pandemic need a strongly coordinated international approach, based on science and evidence, consistent with our democratic values, and utilizing the strengths of private enterprise," the G7 leaders said in a statement coordinated by the United States, which holds the presidency of the group.

In addition to the external travel ban, EU countries continued to impose a haphazard array of new internal border controls that officials, including von der Leyen, said posed a risk to the smooth functioning of the bloc's internal market.

But in a sign of potential underlying tensions, von der Leyen on Monday announced new EU financial support for CureVac, a German biomedical research firm working to develop a COVID-19 vaccine, after reports that the Trump administration had made overtures to buy the company. (U.S. officials denied making such a bid.)

Late Monday night, the finance ministers of eurozone countries announced an initial package of national and joint European fiscal measures and efforts to safeguard liquidity.

"We will protect our citizens and our currency — come what may and with everything we have got," the Eurogroup president, Mário Centeno, said. "Our commitment to provide support in this time of need is unlimited. We will do whatever it takes and more, to restore confidence and support a rapid recovery."

The "and more" seemed inevitable.

In addition to the external travel ban, EU countries continued to impose a haphazard array of new internal border controls that officials, including von der Leyen, said posed a risk to the smooth functioning of the bloc's internal market. Some of the restrictions, including a move by Hungary to seal its borders even to other EU citizens, also seemed to call into question the fundamental freedoms of the EU.

"I understand that the member states, the governments in the member states, do everything they can to protect their people," von der Leyen said. "But indeed we have to be very careful to find the right balance between on one hand restricting the social contacts, and therefore the virus to spread, but on the other hand not to hamper our single market."

In Paris, what was supposed to be the most solemn speech of Macron's presidency left some listeners confused, as he insisted that the movement of French citizens would be severely restricted for 15 days but also that "necessary outings to do a little bit of physical activity" would be permitted.

In any event, Macron insisted that France, and Europe, would triumph.

"We will prevail," he said. "But this period will have taught us a lot. A lot of certainties, beliefs will be swept aside, will be called into question. A lot of things we thought impossible are happening. Let us not be impressed. Let us act with force but let us remember this: The day after, when we will have prevailed, won't be like the day before. We will be stronger morally, we will have learned and I will know, alongside you, to draw the lessons, all the lessons."

Aitor Hernández-Morales, Silvia Sciorilli Borrelli, Cristina Gallardo, Giorgio Leali, Lili Bayer, Saim Saeed, Melissa Heikkilä, Barbara Moens, Cristina Gallardo, Eline Schaart and Hans von der Burchard contributed reporting.