A man who stabbed a police officer at the Bishop International Airport in Flint, Michigan, shouted "Allahu Akbar," according to NBC News reporter Tom Winter.
The FBI is investigating the incident as a potential terrorist attack.
The airport was evacuated Wednesday morning after the police officer, identified as Jeff Neville, was stabbed in the neck.
The officer is in critical condition, according to police.
"Attention: there has been an incident at the airport. An airport police officer has been injured. All passengers are safe and are being evacuated at this time. Please check with your airline for potential cancellations or delays. We will release more information as we have it," the airport said in a statement on Facebook.
Police said a suspect is in custody.
"The cop was on his hands and knees bleeding from his neck," said eyewitness Ken Brown, who spoke to MLive. "I said they need to get him a towel."
City of Flint Police Department also put City Hall on lockdown. Flint Mayor Karen Weaver explained in a statement:
“Authorities have informed Mayor Karen Weaver that a significant security event occurred Wednesday morning at Flint’s Bishop International Airport. Officials say a person of interest in the incident is in custody.
In an abundance of caution, the Flint police chief has stationed police officers around the Flint City Hall complex until further notice. At this time Flint City Hall remains open for business, but with heightened security.
“Right now we are still awaiting more information about the situation at Bishop Airport this morning. My thoughts and prayers are with all of our law enforcement officers who work to service and protect us each and every day. I want the public to know that several agencies are involved and working to ensure the situation is under control. However, at this time we are taking extra precautions just to be safe.”