Presumptive Republican nominee Donald Trump reacted to the terrorist attack on Tuesday in Istanbul that killed at least 28 people at Istanbul’s Ataturk airport, saying terrorism must be kept outside of the United States.

Yet another terrorist attack, this time in Turkey. Will

the world ever realize what is going on? So sad. — Donald J. Trump (@realDonaldTrump) June 28, 2016

We must do everything possible to keep this horrible terrorism outside the United States. — Donald J. Trump (@realDonaldTrump) June 28, 2016

In response to the recent attack, Trump issued the following statement:

Our prayers are with the families of those killed and injured in Istanbul. The whole world is stunned and horrified. The terrorist threat has never been greater. Our enemies are brutal and ruthless and will do anything to murder those who do not bend to their will. We must take steps now to protect America from terrorists, and do everything in our power to improve our security to keep America safe.

Turkish authorities believe three suicide bombers attacked the Istanbul airport on Tuesday, according to Fox News.