Political leaders and others around Europe have expressed their shock at the attacks in Brussels Tuesday. Here is some of their reaction:

— "We will do whatever is necessary to support our friend and ally Belgium in bringing to justice those who are responsible." — President Barack Obama.

— "We are at war. We have been subjected for the last few months in Europe to acts of war." — French Prime Minister Manuel Valls.

— "We realize we face a tragic moment. We have to be calm and show solidarity." — Belgian Prime Minister Charles Michel.

— "The attackers came from within the places that were hit. The threat is global, but the killers are local." — Italian Premier Matteo Renzi.

—"We have repeatedly discussed the issues related to the fight against terrorism, and it's possible to efficiently combat it only by united efforts." — Russian President Vladimir Putin.

— "This is the latest terrorist outrage and today is a day for sympathy and condolence, for enhancing our own security, for working with our own colleagues and offering them every help we can and making sure we are very clear that we will never let these terrorists win." — British Prime Minister David Cameron.

"The King and Queen are devastated by the attacks." — statement from Belgium's royal family. "The emotional thoughts of the King and Queen go first to the victims and their families and the rescue services which are doing everything possible to help the victims."

— "These attacks mark another low by the terrorists in the service of hatred and violence." — EU Council President Donald Tusk.

— Pope Francis said he "condemns once again the blind violence that breeds so much suffering, and implores the gift of peace from God" for all Belgians.

— "Terrorists struck Brussels but it was Europe that was targeted — and all the world that is concerned."— French President Francois Hollande.

—"Our strength lies in our unity, and our free societies will prove to be stronger than terrorism." — German Chancellor Angela Merkel.

— "Europe is being severely tested again. What is necessary now is that we show our collective strength and uphold the values of freedom and solidarity." — Dutch King Willem-Alexander.

— "It is with a heavy heart we learned of these ruthless attacks in Brussels. ... The world must stand united to defeat terrorism." — Salem Al Meslet, of High Negotiations Committee, a coalition of Syrian opposition groups engaged in peace talks in Geneva.

— "Terrorism knows no borders and is a plague to all of us. ... Correct education is the right answer to ignorance and extremism." — Grand Mufti Shawki Ibrahim Abdel-Karim Allam, Egypt's leading religious figure

— "Football is not important today. Training cancelled." — Belgian soccer federation.

—The attacks "have once again shown terrorism's global face." — Turkish Prime Minister Ahmet Davutoglu.

— The attacks "carry a cowardly and barbaric signature" and "Europe must combat terror jointly and determinedly defend its European values" — joint statement from Austrian Chancellor Werner Faymann and Vice-Chancellor Reinhold Mitterlehner.

—"These and other terrorist acts in different countries show that the Olympic values of understanding, respect and peace are more important than ever for our world." — International Olympic Committee President Thomas Bach.

—U.N. spokesman Stephane Dujarric said Ban Ki-moon "is confident that Belgium's and Europe's commitment to human rights, democracy and peaceful coexistence will continue to be the true and lasting response to the hatred and violence of which they became a victim today."