The European Union has warned Washington about tightening visa-free travel to the United States.
Diplomats from the 28-member group on Monday warned they could respond in kind if the US implemented plans to end visa-free entry for some EU nationals.
The EU ambassador to the US described the imminent approval of tightening Visa Waiver Program as an indiscriminate action against over 13 million European citizens who travel to the US annually.
David O'Sullivan said the move would be counterproductive and trigger legally-mandated reciprocal measures.
He also said the measure will not only fail to increase security but also hurt economies on both sides.
"Compulsory biometric checks at the port of origin would represent the de facto introduction of a visa regime in all but name," O'Sullivan said in an editorial in The Hill, on behalf of ambassadors to the US of EU member states.
Last week, the US House of Representatives voted in support of the program under the pretext of preventing likely terror attacks.
The measure, which is yet to be approved by the Senate and the White House, would prevent nationals from 38 countries who have visited Iran, Syria, Sudan or Iraq in the past five years from entering the US without a visa.
The US House of Representatives measure came in the wake of the November 13 Paris attacks that killed at least 130 people and injured hundreds more.
ISIL terrorists, who were initially trained by the CIA in Jordan in 2012 to destabilize the Syrian government, have claimed responsibility for the deadly attacks in France.
However, some independent American analysts, like former US Treasury official Paul Craig Roberts, say the United States and NATO actually orchestrated the Paris attacks as a “false flag” to tighten their borders and enter the Syrian war in order to counter Russia, which has been conducting air strikes in Syria against ISIL terrorists since September 30.