Syria has protested against the tighter screening of Syrian passenger, defining the measures as unfriendly discriminatory procedures and warning it would take reciprocal measures if the move was not annulled.
The extra screening measures were put in place following the attempted Christmas Day bombing of a US Airliner by a Nigerian terrorist.
The Obama administration has also increased its security, especially for in-bound flights from 14 terrorist-prone nations such as Cuba, Iran, Sudan, Syria, Afghanistan, Algeria, Lebanon, Libya, Iraq, Nigeria, Pakistan, Saudi Arabia, Somalia and Yemen.
Passengers from the listed countries will undergo compulsory enhanced screening, according to reports.
Syria is on the US State Department's list of state sponsors of terrorism along with Cuba, Iran and Sudan.
Last week Nigeria, Libya, Cuba, Pakistan and Algeria formally protested against the US listing them as terror nations.