British spies say 23,000 jihadists remain at large in the UK

British intelligence officers have said that there may be as many as 23,000 jihadist extremists living in the U.K.

Government officials have stated that 3,000 people from the group have been deemed as a threat and are under investigation or active monitoring, while the other 20,000 have been featured in previous inquiries and were categorized as posing a "residual risk," according to The Australian.

Ben Wallace, the UK Security Minister, said that the existence of a database of 23,000 potential terrorists "reveal the scale of the challenge from terrorism in the 21st century." "Never has it been more important to invest in intelligence-led policing," he remarked.

The Australian noted that MI5 is only capable of investigating about 3,000 individuals at a time. People are added to and removed from the list of "live" suspects based on assessments of who poses the greatest risks.

Sources say that the pool of former suspects has grown to 20,000 during the years of Islamist threat since 2001. There is concern that the efforts of intelligence agencies to detect former subjects of interest who have returned to extremism have been inadequate.

The revelation comes as the authorities released new photos of 22-year-old Salman Abedi, who carried out the suicide bombing in Manchester that claimed 22 lives and injured 119 others. The newly released images were the first to show what the bombing suspect looked like when he carried out the attack.

The police are searching 14 locations in connection with the attack, while 11 men are being detained on suspicion of terror offenses.

"We have made significant progress in this fast moving and complex investigation, working with the national counter terrorism policing network and UK intelligence partners and securing the arrests of 11 people who remain in custody," said a statement from Greater Manchester Police.

"The level of resources we have available to us remains the same as we continue to take positive action so you will notice additional officers, including armed officers, on patrol especially at a number of events this weekend to ensure the security and safety of everyone but it's important that people remain alert and vigilant," it continued.

The British government has lowered the terror threat level from "critical" to "severe" on Saturday following the arrests, which means that an attack is still highly likely if not imminent.