WATCH: Donald Trump Reacts to Brussels Terror Attacks

'Equivalent to an Attack on Washington': Expert Explains How Brussels Is 'Symbolic'

Trump Says His Campaign Is a 'Movement': 'Not So Silent, But Definitely a Majority'

Several of the 2016 presidential candidates took to Twitter this morning following the terror attacks in Brussels, Belgium, that left at least 31 dead and dozens injured.

See what Donald Trump, Ted Cruz, John Kasich and Hillary Clinton had to say below.

'It Comes with the Territory': Eric Trump Speaks Out on Threatening Letter

'The Barrier to Peace Is Not Israel': Cruz Slams Trump Over 'Neutral' Comment

WATCH: Trump Offers Woman a Job in the Middle of His Press Conference