European countries on Tuesday vowed to defend democracy against terrorism after blasts at Brussels airport and in the EU’s institutional heart left at least 26 dead and dozens injured.

European countries on Tuesday vowed to defend democracy against terrorism after blasts at Brussels airport and in the EU's institutional heart left at least 26 dead and dozens injured.

"The whole of Europe has been hit," French President Francois Hollande declared, urging the continent to take "vital steps in the face of the seriousness of the threat."

As country after country voiced anger and dismay, Russia and Turkey -- themselves targets of deadly attacks in the last eight months -- said the blasts highlighted the need to fight terrorism of every hue and across all borders.

"This is a day of tragedy, a black day," Michel said on national television.

"Our Union's capital is under attack. We mourn the dead and pledge to conquer terror through democracy," the Greek foreign ministry said in a tweet.

It added in French, "Nous sommes tous Bruxellois," -- "We are all citizens of Brussels."

Spanish Prime Minister Mariano Rajoy said: "Terrorism will never defeat us. The union of democrats in Europe will always prevail over barbarism and madness."

Swedish Prime Minister Stefan Lofven described the blasts as "an attack against democratic Europe. We will never accept that terrorists attack our open societies."

Italian Prime Minister Matteo Renzi tweeted: "My heart and spirit in Brussels, Europe," while Interior Minister Angelino Alfano said "the Brussels attacks strike the heart of our Europe."

"The fight against terrorism is the duty of every one of us," Polish President Andrzej Duda said.

Serbian Prime Minister Aleksandar Vucic said the attacks "jeopardize all the values of civilization that we strongly support."

European Union president Donald Tusk condemned the blasts as "terrorist attacks."

"These attacks mark another low by the terrorists in the service of hatred and violence," he said in a statement.

-- Global action on terror --

In Paris, the Eiffel Tower was to be lit up in the colours of Belgium on Tuesday night in homage to "the victims, their families and the Belgian people," said city mayor Anne Hidalgo.

Russia and Turkey said the blasts underscored the global need to fight terrorism across borders.

A Russian plane was downed by a bomb over the Sinai Peninsula in October that killed 224 people.

In Moscow, Russian President Vladimir Putin lashed out at what he called "barbarous crimes" and expressed his condolence with Belgium.

"(They) demonstrate once again that terrorism has no borders and threatens people around the world. Fighting this evil calls for the most active international cooperation."

Turkish Prime Minister Ahmet Davutoglu said the attacks "have once against shown the worldwide character of terrorism."

Foreign Minister Volkan Bozkir added: "Every effort must continue to fight terrorism without distinction and those who support terrorism."