The US Transportation Security Administration has issued new security measures for all flights departing from any foreign location to the US, said American Airlines.
With the airlines undertaking enhanced security measures outside and inside the plane, passengers are being put through additional security checks at the airports.
President Barack Obama, who is in Hawaii on a vacation, has been monitoring the situation and has called for 'all appropriate measures'.
In a statement, homeland security spokesperson Sara Kuban informed the passengers of "additional screening measures put into place to ensure the safety of the travelling public on domestic and international flights."
"We encourage the travelling public to be observant and aware of their surroundings and report any suspicious behaviour to law enforcement officials," the statement adds.
Foreign airlines such as British Airways and Air Canada have already taken measures to educate their fliers of these new security measures and have advised the passengers to arrive at the airport early to allow extra time to clear security screening.