UPDATE 11:49 a.m. ET:The Associated Press reports that the death toll has risen to 31. Dozens of other have been injured. CNN is also reporting that ISIS has taken responsibility for the explosions.

On Tuesday, March 22, terrorists attacked a subway station and airport in Brussels, Belgium, which resulted in dozens of fatalities, the Associated Pressand The New York Times. At least 31 have been confirmed dead.

Two explosions, at least one of which officials believe to have come from a suicide bomber, were set off inside the city’s main international airport and a third went off at the city’s Maelbeek metro station. The attacks happened around 8 a.m. local time.

French Prime Minister Manuel Valls told the AP, “We are at war. We have been subjected for the last few months in Europe to acts of war.”

In November, Paris was the subject of several horrific terrorist attacks that resulted in 130 deaths. The new attacks in Brussels happened four days after the capture of Salah Abdeslam, who is believed to be the only survivor of the 10 men responsible for the bombings in Paris.

All flights and public transportation in Brussels have been shut down for the day as security has been increased both in the Belgian capital and in major cities around the world. Although there is no known connection to New York City, the New York Police Department confirmed to ET that it has increased its presence around the city.

Following the news of the attacks, several stars tweeted their support for the city.

“Beyond sad and outraged that the scourge of the earth continue to feel the need to kill innocent people everywhere. #Brussels #WeStandWithU,” Josh Gad wrote.

Presidential hopeful Donald Trump, also tweeted, “Do you all remember how beautiful and safe a place Brussels was. Not anymore, it is from a different world! U.S. must be vigilant and smart!”

Democratic candidate Hillary Clinton also released an official statement regarding the attacks on Tuesday, saying, “Terrorists have once again struck at the heart of Europe, but their campaign of hate and fear will not succeed. The people of Brussels, of Europe, and of the world will not be intimidated by these vicious killers. Today Americans stand in solidarity with our European allies. Our thoughts and prayers are with the families of those killed and wounded, and all the people of Belgium. These terrorists seek to undermine the democratic values that are the foundation of our alliance and our way of life, but they will never succeed. Today's attacks will only strengthen our resolve to stand together as allies and defeat terrorism and radical jihadism around the world.”