BRUSSELS — Authorities in Europe and beyond tightened security at airports, on subways, at the borders and on city streets after deadly attacks occurred Tuesday at the Brussels airport and subway station.

Belgian Health Minister Maggie de Block said 11 people were dead and 81 injured in twin explosions at Brussels’ Zaventern Airport. The Brussels mayor said at least 20 people died and 106 were injured in the attack on the Maelbeek subway station.

With Brussels on lockdown and the French prime minister saying that Europe is “at war”, European leaders held emergency security meetings and deployed more police, explosives experts, sniffer dogs and plainclothes officers at key points across the continent.

Eurostar has suspended high-speed rail service to Brussels-Midi station following the attacks. The rail service links London with Brussels and Paris via the Channel Tunnel.

The Paris airport authority said security was tightened at all Paris airports soon after the Brussels explosions on Tuesday morning. Airports in London, Prague, Amsterdam, Vienna and many others also saw increased security. Both of London’s major airports, Gatwick and Heathrow, stepped up security, as well as the rail system in Germany.

According to New York Governor Cuomo, security has been stepped up at LaGuardia, JFK and Newark and Stewart International Airport. All flights to and from Brussels from JFK/EWR have been cancelled today.

.@NYGovCuomo statement on #Belgium: stepped up security from @PANYNJ Police @NY_NJAirports @PATHTrain @PABusTerminal https://t.co/8gEl5Y6jsC

— EWR JFK LGA SWF (@NY_NJairports) March 22, 2016

All flights to and from Brussels-JFK/EWR have been canceled today. https://t.co/UtqqhEJa0j

— EWR JFK LGA SWF (@NY_NJairports) March 22, 2016

Global Affairs Canada says it has no reports of any Canadian citizens being affected by Tuesday’s attacks.

In an advisory posted on its website early Tuesday, the federal ministry said while there is no nationwide advisory in effect for Belgium, Canadians should exercise a “high degree of caution due to the current elevated threat of terrorism.’”

More than 200 flights to Brussels were diverted or cancelled, according to flight tracking service Flightradar24.

Air Canada has issued a travel alert for customers trying to travel through the Brussels airport, advising flights may be cancelled or delayed. Air Canada spokesman Peter Fitzpatrick said the airline’s staff and crew in Brussels were safe and sound and that one flight had been diverted to Paris.

UNWTO released a statement on behalf of the international tourism community. “On behalf of the international tourism community, UNWTO conveys its heartfelt condolences to the families and friends of the victims and expresses its full solidarity with the people and the Government of Belgium,” said UNWTO Secretary-General, Taleb Rifai. “This is not an attack on Belgium, it is an attack on us all and sadly these tragic events remind us again that we are facing a global threat that needs to be addressed globally,” he added.

Here are the latest tweets and messages from travel organizations regarding today’s terror attacks:

(1/2) Our thoughts are with those affected by the tragic events in Brussels this morning.

— Contiki Holidays (@ContikiCanada) March 22, 2016

(2/2) We can confirm that no Contiki travellers were in Brussels at the time of these events. More info: https://t.co/Rt2JsISWAC

— Contiki Holidays (@ContikiCanada) March 22, 2016

WTTC statement following the attacks in Brussels, 22 March 2016: https://t.co/TUCeO1i76S

— WTTC (@WTTC) March 22, 2016

Our thoughts go to the victims of events that happened at #Zaventem #brusselsairport this morning & our support to their families & friends

— IATA (@IATA) March 22, 2016

Our thoughts go to the families and friends of the victims in @brussels

— UNWTO (@UNWTO) March 22, 2016

From Meliá we extend our condolences to the families of the attacks in Brussels.

— MELIÃ HOTELS INT (@MeliaHotelsInt) March 22, 2016