ISIS appeared to threaten an attack on Washington D.C., and any country launching air strikes on Syria, in a new video from the terror group that surfaced online Monday.

The video, which appeared on ISIS propaganda sites, starts with news coverage of the Paris attacks that killed at least 129 people. It then cuts to a man in a turban, identified as Al Ghareeb the Algerian, warning countries that band together against Syria after the France massacre.

�We say to the states that take part in the crusader campaign that, by God, you will have a day, God willing, like France's and by God, as we struck France in the center of its abode in Paris, then we swear that we will strike America at its center in Washington,� the man says, according to translations of the video.The man never mentions a specific target in America's capital.

He also warns of more attacks to come in Europe, telling countries there they "will be unable to stop us because today we are much stronger than before."

Another man in the video, identified asAl Karrar the Iraqi, tells French PresidentFrancois Hollande the terrorists will"negotiate with you in the trenches and not in the hotels."

The authenticity of the video has not been independently verified.

Capitol Police stepped up security on Capitol Hill. An email warned lawmakers and their aides to use tunnels connecting the Capitol to the House and Senate office buildings "out of an abundance of caution," but said there is no particular danger.

"While there currently is no specific threat to the Capitol Complex it will always be an appealing target," the message says.

D.C. police, too are monitoring the message.

�The Metropolitan Police Department is working collaboratively with local and federal law enforcement and homeland security agencies to ensure the security of Washington, DC.," the department said in a statement. "We will continue to monitor intelligence reports and work with our federal partners to authenticate and determine the credibility of this new threat. MPD will maintain a proactive posture in response to the tragic events in Paris and the recent threats against our city. Additionally, our resource deployment and staffing have been enhanced.�

The authenticity of the video has not been independently verified.

Capitol Police stepped up security on Capitol Hill. An email warned lawmakers and their aides to use tunnels connecting the Capitol to the House and Senate office buildings "out of an abundance of caution," but said there is no particular danger.

"While there currently is no specific threat to the Capitol Complex it will always be an appealing target," the message says.

D.C. police, too are monitoring the message.

�The Metropolitan Police Department is working collaboratively with local and federal law enforcement and homeland security agencies to ensure the security of Washington, DC.," the department said in a statement. "We will continue to monitor intelligence reports and work with our federal partners to authenticate and determine the credibility of this new threat. MPD will maintain a proactive posture in response to the tragic events in Paris and the recent threats against our city. Additionally, our resource deployment and staffing have been enhanced.�

France had been bombing ISIS targets in Syria and Iraq for months already, but the new strikes showed a severe escalation of force responding to a massacre that French President Francois Hollande has called �an act of war.�

By Nydaily News