The United States says it now launches a new investigation into suspected ISIL group sympathizers almost every day.

The United States says it now launches a new investigation into suspected ISIL group sympathizers almost every day.

A senior administration official warned the Congress on Wednesday of "brinkmanship" over intelligence gathering powers that put national security at risk at a sensitive time.

 "We are opening new investigations daily, particularly the ISIL threat," said the official.

"They have a strategy now of encouraging anyone, essentially, to take arms and commit a terrorist attack inside the United States," said the official, speaking on condition of anonymity.

"New individuals" are "popping up pretty much daily on the radar screen in our current threat environment."

The US official said that agencies like the Federal Bureau of Investigation had to "try to figure out is this the real deal, someone who is going to commit a terrorist act, or not."  

"What the FBI is looking for is connectivity, whether they can show that that person has been in touch with one of the terrorists overseas, in Syria or Iraq."

The US is leading an international coalition against the Takfiri group which is operating in Iraq and Syria. The coalition carries out air strikes on the ISIL positions in these two countries.

However, US’ intention to fight ISIL has been widely criticized, with several media reports said the coalition warplanes had repeatedly airdropped weapons and supplies to militants in Syria and Iraq.

Earlier this week, General Qassem Suleimani, the head of an elite unit in Iran’s Revolutionary Guard, said the US "no will" to stop ISIL, accusing Washington of supporting the terrorist group.