Republican and Democratic leaders of intelligence committees from both the Senate and House called on President Barack Obama to confront ISIS militants, warning of a possible attack on the United States or its European allies.
"This is a group of people who are extraordinarily dangerous, and they'll kill with abandon," Sen. Dianne Feinstein, the California Democrat who leads the Senate intelligence panel, said Sunday on NBC's "Meet the Press."
"ISIL would like to have a Western-style attack to continue this notion that they are the leading jihadist group in the world," added Rep. Mike Rogers, a Republican from Michigan and head of the House Intelligence Committee, speaking on "Fox News Sunday."
ISIS, or the Islamic State of Iraq and Syria, is an al-Qaeda offshoot which has gained control over vast swaths of Syria and Iraq. It is also known as the Islamic State and ISIL, and is aimed at forming an Islamic emirate in the Levant, a region also known as the Eastern Mediterranean, through "jihad." The group has asked minorities living in areas under its control to flee, convert to Islam, or be killed.
Rogers said ISIS terrorists want to launch an attack to raise money and recruit more fighters internationally.
The U.S. government is reportedly tracking at least 300 Americans suspected of fighting for the terror outfit. And hundreds of British and European nationals are also said to part of the terror group.
Last month, ISIS militants beheaded American journalist James Foley. Hundreds of members of the Christian and Yazidi minorities have also been killed, and tens of thousands of them were forced to flee their homes.
"They have announced that they don't intend to stop. They have announced that they will come after us if they can, that they will, quote, 'spill our blood,'" Feinstein stated.
Rogers added his concern, saying "… we don't know every single person that has an American passport that has gone and trained and learned how to fight."
However, some Democratic lawmakers want to take a more cautious approach.
"It is extremely urgent, but you don't just rush in," Rep. C.A. Dutch Ruppersberger of Maryland, a Democrat in the House committee, told CNN's "State of the Union."
"We can't simply bomb first and ask questions later," added Rep. Adam Smith, a Washington state Democrat on the House Armed Services Committee, speaking to CBS' "Face the Nation."
ISIS exploited the growing tension between the Sunni minority and Shia-led government in Iraq earlier this year by capturing the predominantly Sunni city of Fallujah in west Iraq. It also gained control of many parts of the city of Ramadi and has its fighters in many towns near the Turkish and Syrian borders, and other cities.
The U.S.-based Judicial Watch said Friday that ISIS operatives are just across the border from Texas, and are planning to launch a car bomb attack.
ISIS is operating in Juarez across El Paso, Texas, where violent crimes are rampant, it said, adding that an attack is "coming very soon."