Donald Trump weighed in on the Brussels attacks in characteristically forthright fashion Tuesday | Alex Wong/Getty Images Trump on Brussels: Told you so Rivals accuse GOP front-runner of stoking fear amid crisis.

Shortly after news broke of the terrorist attacks in Brussels, Donald Trump was on television. He didn’t wait to consult with the foreign-policy advisors he announced a day earlier; instead he quickly condemned the attacks and argued that they serve as further rationale for some of his most controversial ideas, from closing America’s borders to allowing the greater use torture in the war on terrorists.

Touring the morning talk-show circuit following multiple explosions throughout the Belgian capital on Tuesday, the Republican front-runner stressed that he is the strongest candidate on border control, an issue he said he has emphasized more than any other GOP contender.

Trump said immigrants aren’t assimilating to other countries’ cultures and that America has to be vigilant.

“We have no idea what’s happening. Our government has absolutely no idea what’s happening, but they’re coming into our country,” predicted Trump, offering no further evidence or specificity. “They’re coming in by the thousands and just watch what happens — I’m a pretty good prognosticator — just watch what happens over the years. It won’t be pretty.”

According to Belgian authorities, at least 31 people are dead and more than 170 are injured following a series of explosions — two at an airport and another at a metro station not far from the headquarters of the European Union.

Trump, who called for a temporary ban on Muslims in December following terror attacks, credited his position on border control for his lead in the race for the Republican nomination.

Hillary Clinton offered her condolences and said the hate and fear campaign of the terrorists who struck Europe will not succeed.

“This is what I’ve been saying for a long time, and I guess it’s at least a small part of the reason why I’m the No. 1 front-runner,” he told “Fox & Friends” in a phone interview. “I mean, people are very concerned about this, and they’re very concerned about the security of this country.”

Trump’s response to this international crisis offers the country—and his rivals—another glimpse into how he might handle the more sobering aspects of serving as commander in chief. As with his candidacy as a whole, his reaction provides another Rorschach test: while his blunt statements of strength remind supporters of what they like about Trump, they offer his rivals an opportunity to argue anew that the Manhattan billionaire is too unsophisticated and unprepared to grapple with the difficult decisions that will confront a president.

The other two Republican candidates still vying for the nomination, Ted Cruz and John Kasich, insinuated that Trump's words were hollow and intended to stoke public fears. "Governor Kasich believes that leadership isn't about playing on people's fears and driving panic," said Chris Schrimpf, Kasich's spokesman. "It is about responding calmly, bringing people together and talking about the way forward. That's what Governor Kasich does in times of crisis."

Cruz, who has been frustrated by his inability to get to Trump’s right on immigration, attempted to portray his rival as unserious. “We don’t need a pep talk,” Cruz said Tuesday morning on Glenn Beck’s radio show. “What we need is serious leadership that keeps us safe.”

In a press conference earlier Tuesday morning, the Texas senator focused attention on Trump’s statements Monday that the United States should consider reducing its involvement in NATO because it costs too much.

"It is striking that the day after Donald Trump called for weakening NATO, withdrawing from NATO, we see Brussels, where NATO is headquartered, the subject of a radical Islamic terror attack," Cruz said. "Donald Trump is wrong that America should withdraw from the world and abandon our allies. Donald Trump is wrong that American should retreat from Europe, retreat from NATO, hand Putin a major victory and while he's at it hand ISIS a major victory.”

John Kasich’s top strategist, John Weaver, criticized Trump along the same lines. “Trump wants to shrink NATO at time when America needs to lead NATO/world and eliminate terrorists. We need a steady, strong leader @JohnKasich,” he tweeted.

Trump insisted that the U.S. has to be careful and warned that acts of terrorism will only multiply.

“I think this whole thing will get worse as time goes by,” he said. “It’s being, you know, perpetrated all over the place now. Brussels is in very bad shape, but many cities will be this way with what’s taking place, and it’s really the policies of people who don’t know what they’re doing.”

Later Tuesday morning, Trump tweeted: “President Obama looks and sounds so ridiculous making his speech in Cuba, especially in the shadows of Brussels. He is being treated badly!”

Kasich expressed his thoughts and prayers for those affected by the Brussels attacks and said he was sickened by what took place.

President Obama and other Cabinet officials have been briefed, and many of the remaining presidential candidates have spoken out.

In a statement released by her campaign, Democratic front-runner Hillary Clinton offered her condolences and said the hate and fear campaign of the terrorists who struck Europe will not succeed. Later, she scolded others for using the attacks to promote torture and hate.

"We can be strong and smart without advocating torture or bigotry. We will not let fear dictate our foreign policy," she tweeted.

“The people of Brussels, of Europe, and of the world will not be intimidated by these vicious killers,” she said, adding that the attacks will strengthen America’s resolve to stand beside its allies to defeat terrorism.

And Bernie Sanders called for unity to destroy the Islamic State, which claimed responsibility for the Brussels attack later Tuesday. “We offer our deepest condolences to the families who lost loved ones in this barbaric attack and to the people of Brussels who were the target of another owardly attempt to terrorize innocent civilians,” Sanders said. “We stand with our European allies to offer any necessary assistance in these difficult times.”

In a statement, Kasich expressed his thoughts and prayers for those affected by the Brussels attacks and said he was sickened by what took place.

“The wave of terror that has been unleashed in Europe and elsewhere around the world are attacks against our very way of life and against the democratic values upon which our political systems have been built,” the Ohio governor said, calling on the U.S. and its allies to jointly reject terror and work together to “root out and destroy the perpetrators of such acts of evil.”

Cruz briefly offered his condolences before insisting that the explosions in Brussels were merely “the latest in a string of coordinated attacks” and vowing that America will defeat radical Islamic terrorism.

“Radical Islam is at war with us. For over seven years we have had a president who refuses to acknowledge this reality,” the Texas senator wrote in a Facebook post. “And the truth is, we can never hope to defeat this evil so long as we refuse to even name it. That ends on January 20, 2017, when I am sworn in as president.”

The series of explosions that struck Brussels on Tuesday followed the Friday arrest of Salah Abdeslam, a suspect in the Paris terror attacks in November that left 130 people dead. Abdeslam was apprehended during a raid in Brussels.