President Barack Obama has ordered that all American flags in the U.S. be flown at half-staff through Saturday out of respect for victims of the Brussels attack.

Obama said in a proclamation issued hours after Tuesday's attacks that "the American people stand with the people of Brussels. We will do whatever it takes, working with nations and peoples around the world, to bring the perpetrators of these attacks to justice, and to go after terrorists who threaten our people."

Law enforcement groups are reviewing security protocols at American airports following the attack. There's no expectation for there to be any big changes at airports following this attack but at Waukesha County Technical College (WCTC) teachers are continuing to review the developing situation.

Brain Dorow is Dean of Criminal Justice and Homeland Security departments at WCTC. He said that even though the attack happened in Belgium there is a lot to consider for the United States.

"Was there a breach in security that can be improved for the future? I represent the training arm of training thousands of law enforcement officers. We look at all these very seriously. Especially when it comes to tactics. If there's a tactic that we can change, that we can add something to it, that's going to save lives - we will do that," Dorow said.