Federal Bureau of Investigation director Christopher Wray on Thursday expressed concern that foreign terrorist organisations (FTOs), such as the Islamic State and Al Qaeda, may either launch or inspire large-scale attacks against the United States.
The head of the FBI said in a prepared statement before the US Senate Committee on the Judiciary.
He said the FBI remains concerned that FTOs and their affiliates, intend to carry out or inspire large-scale attacks in the United States.
"Despite its loss of physical territory in Iraq and Syria, ISIS remains relentless in its campaign of violence against the United States and our partners -- both here at home and overseas," Wray said.
This concern comes as the US announced the killing of the Al Qaeda chief in a safe house in the heart of Kabul.
Though the Islamic outfit confirmed the US drone strike in Kabul but denied the presence of the Al Qaeda chief.
Wary said that ISIS and its supporters continue to aggressively promote its hate-fueled rhetoric and attract like-minded violent extremists with a willingness to conduct attacks against the United States and our interests abroad.
'ISIS' successful use of social media and messaging applications to attract individuals is of continued concern to us. Like other foreign terrorist groups, ISIS advocates for lone offender attacks in the United States and Western countries via videos and other English language propaganda that have, at times, specifically advocated for attacks against civilians, the military, law enforcement and intelligence community personnel,' he said.
'Al Qaeda maintains its desire to both conduct and inspire large-scale, spectacular attacks,' he added.
Earlier this week, the Biden administration said that by hosting the leader of Al Qaeda in Kabul, the Taliban violated the Doha Agreement and repeated assurances that they would not allow Afghan territory to be used by terrorists to threaten the security of other countries.
'They also betrayed the Afghan people and their own stated desire for recognition from and normalization with the international community,' US State Department said in a statement.
On July 31, the United States conducted a precision counterterrorism strike in Afghanistan that killed Ayman al Zawahiri, Osama bin Laden's deputy and successor as leader of Al Qaeda.
Al Zawahiri was one of the masterminds of the attacks against the United States on September 11, 2001, and had continued to urge his followers to attack the United States.
Following al Zawahiri's death, supporters of Al Qaeda, or its affiliated terrorist organisations, may seek to attack US facilities, personnel, or citizens.
After the killing of Zawahri, the US warned Americans overseas to be on high alert.
"As terrorist attacks often occur without warning, U.S. citizens are strongly encouraged to maintain a high level of vigilance and practice good situational awareness when traveling abroad," State Department said in an alert.
It added that there is a 'higher potential for anti-American violence after death, and that current information suggests terrorist groups are plotting attacks against US interests in multiple regions across the globe'.