Washington: The Islamic State (IS) is training and attempting to deploy operatives for further attacks on the West, CIA Director John Brennan told the Congress, while confirming the Orlando gunman had no direct links to the extremist group. "IS has a large cadre of western fighters who could potentially serve as operatives for attacks in the West," Brennan, on Thursday told the Senate Select Committee on Intelligence, warning the group may infiltrate refugees into western nations. "Unfortunately, despite all our progress against IS on the battlefield and in the financial realm, our efforts have not reduced the group's terrorism capability and global reach," said the intelligence chief. According to Brennan, the IS has lost "large stretches" of territory in Iraq and Syria but still has about 18,000 to 22,00 fighters there and its branch in Libya is "probably the most developed and the most dangerous", echoing concerns that Libya's close proximity to Europe is a problem. He testified to the Congress that the IS has between 5,000 and 8,000 fighters in Libya, plus some 7,000 in Nigeria and hundreds more in Egypt, Afghanistan and Pakistan. Moreover, "as the pressure mounts on IS, we judge that it will intensify its global terror campaign to maintain its dominance of the global terrorism agenda," said Brennan. As for the Orlando shooting which left 50 dead including the shooter Omar Mateen on June 12, Brennan said the current investigation has not been able to uncover any direct link between the Afghan-origin shooter and a foreign terrorist organisation. However, "lone wolf" attackers who are inspired by but not under the direct control of terror groups represent "an exceptionally challenging issue for the intelligence community", he noted. The CIA is sharing intelligence with the FBI to help identify potential lone-wolf attackers, but the CIA's responsibility is to gather information about operations overseas, he added. Both Donald Trump and Hillary Clinton are expected to receive classified briefings from intelligence agencies once they officially become the Republican and Democratic presidential nominees in July.