CIA Director John O. Brennan said it's "clear" that the Islamic State has "an external agenda [and] that they are determined to carry out these types of attacks." Paris was not "the only operation that ISIL has in the pipeline," he said.
This undated image made available in the Islamic State's English-language magazine Dabiq, shows Abdelhamid Abaaoud, who grew up in the Molenbeek-Saint-Jean neighborhood of Belgian capital. Abaaoud was identified by French authorities on Monday as the presumed mastermind of the terror attacks Friday in Paris.
Special intervention forces prepare to enter a house in Brussels on Monday in search of Salah Abdeslam, a suspect of the terrorist attacks in Paris. French police had him in their grasp but let him go after checking his ID. (Associated Press)
French, left, and German police control cars at the French-German border near Saarbruecken, southwestern Germany, Sunday Nov. 15, 2015. Multiple attacks across Paris on Friday night have left scores dead and hundreds injured. ( (Oliver Dietze/dpa via AP)
A Washington Metropolitan Police officer works on 15th St NW at Pennsylvania Avenue near the White House in Washington on Monday, Nov. 16, 2015, in the wake of the terrorist attacks in Paris. (Photo/Jacquelyn Martin)
This undated image made available in the Islamic State's English-language magazine Dabiq, shows Belgian national Abdelhamid Abaaoud. Abaaoud, the child of Moroccan immigrants who grew up in the Belgian capital’s Molenbeek-Saint-Jean neighborhood, was identified by French authorities on Monday Nov. 16, 2015, as the presumed mastermind of the terror attacks last Friday in Paris that killed over a hundred people and injured hundreds more. (Militant Photo via AP)
Some demonstrators sat down in the street as others chanted at Minneapolis police officers at the side entrance to the 4th Precinct station on Morgan Ave. N. Sunday, Nov. 15, 2015, in Minneapolis, after a man was shot by Minneapolis police early Sunday morning. (Jeff Wheeler/Star Tribune via AP)
National Edition News cover for November 16, 2015 - Obama: U.S. still open to refugees : FILE - In this Monday, Aug. 24, 2015 file photo, migrants wait to register with the police in refugee center in the southern Serbian town of Presevo. Balkan authorities are tracking the travels of a man whose Syrian passport was found next to a dead suicide bomber at the national stadium in Paris, France, on Friday night following the terror attacks. Serbian police say he registered at its border entry with Macedonia on Oct. 7, but it is not clear whether the passport was real or fake. (AP Photo/Darko Vojinovic, File)
Notre Dame cathedral in Paris hosted a national service Sunday to remember the victims of the Friday terrorist attacks. By Sunday night, as French military forces pounded the Islamic State's self-styled capital in Raqqa, Syria, officials in Belgium had detained seven people in connection with the attacks. (Associated Press)
France launched massive airstrikes on the Islamic State group's de-facto capital in Syria on Sunday night, destroying a jihadi training camp and a munitions dump in the city of Raqqa, where Iraqi intelligence officials say the attacks on Paris were planned. (Associated Press)
Beauty amid tragedy: Flowers fill a bullet hole in the window of the Carillon cafe in Paris. French troops deployed around the city Sunday, and tourist sites stood shuttered after the country's deadliest violence since World War II.
People mourn for the victims of the deadly attacks in Paris, outside the French embassy in Warsaw, Poland, Saturday, Nov. 14, 2015. French President Francois Hollande said more than 120 people died Friday night in shootings at Paris cafes, suicide bombings near France's national stadium and a hostage-taking slaughter inside a concert hall. (AP Photo/Alik Keplicz)