On Sunday, a man was arrested at the Detroit Metropolitan Airport in Romulus, Michigan after authorities found a knife in his shoe, they said.

According to Associated Press, the man, whose name has not yet been released, was found to be carrying a knife underneath the liner of one of his shoes on Sunday morning. The knife was discovered during a security screening of the passenger.

The Transportation Security Administration said that following the discovery of the knife, police confiscated it and subsequently arrested the man. According to TSA, proper protocol would have been to pack the knife in checked luggage.

This week, Los Angeles Times reported that the TSA has seen an increase in credit card knives, which are knives designed to look like a thick credit card but contain a folded blade. According to Ross Fenstein, a TSA spokesman, 491 such knives have been found on passengers this year -- an average of approximately 20 knives a week. They are available on the Internet for $4 to $15 and are "lightweight surgical knives" useful for cutting seatbelts when necessary, according to a description by Iain Sinclair, a British manufacturer of the tool.

In addition, the TSA reportedly found a record-breaking 65 firearms on airline passengers in one week in May. This included 45 guns loaded with bullets.

Fox News reports that Homeland Secretary Jeh Johnson recently asked TSA to buff up their security at various international airports that feature direct flights into the country. An anonymous Homeland Security Department official, who Fox News said is not allowed to talk about new policy, explained that the TSA can set screening standards and procedures for flights entering the U.S. from overseas.

On Sunday, Johnson was vague when asked whether heightened security measures found at airports around the world would soon be seen in U.S. airports.

"The screening we have right now domestically, from one domestic airport to another is pretty robust, as the American traveling public knows," Johnson said in an interview with NBC's "Meet the Press." "In this instance we felt that it was important to crank it up some at the last point of departure airports, and we'll continually evaluate the situation."
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