With nearly 40 US casualties in Afghanistan and Taliban leader Mullah Mohamed Omar and Osama Bin Laden making defiant remarks in the media, the war against terror is far from over, reports Anayat Durrani from Washington Click to view caption Mopping up efforts in Afghanistan have resumed as United States and coalition allies step up Operation Mountain Lion "to locate, isolate, close with and destroy" any remnants of Al-Qa'eda and the Taliban in eastern Afghanistan. The US-led coalition patrolling the area has increasingly come across small groups of dispersed enemy fighters. Taliban and Al-Qa'eda fighters are believed to be hiding in the mountainous area of eastern Afghanistan near the cities of Khost and Gardez where they have been taking refuge for the past few months. US officials believe that since March small groups of fighters have scattered across eastern Afghanistan, some fleeing across the border to Pakistan while others have blended into the local communities. Large groups of Taliban and Al-Qa'eda forces have not been encountered since March, when US-led troops battled several hundred enemy forces in the Shah-e-Kot valley. "As a result of Operation Anaconda, the willingness of Al-Qa'eda and Taliban to form large groups that will stand and fight against our forces is now dissipated," said Marine Corps Lt Gen Gregory Newbold at a Pentagon news conference on Monday. "They've changed their tactics. They operate in small groups to avoid contact with our forces." Newbold said that Al-Qa'eda and the Taliban now move in small groups of between three and 12 men. Newbold said they have been using coalition and US reconnaissance to rule out or pinpoint areas in which dispersed Taliban and Al-Qa'eda forces may be present. "As we do that and we locate their forces, we go after them -- actions over the last two weeks have been pretty symptomatic of that." When enemy fighters have been located, coalition teams are sent into the mountains in a "checkerboard fashion" to isolate areas where they may have regrouped or have the greatest potential to surface. "In some cases these are remnants of Taliban forces or Al-Qa'eda that have come from other portions of Afghanistan," he said. "I'm certain that some of them are living in caves but others may come from villages." The latest American casualty in the war in Afghanistan occurred on Sunday. Newbold reported that Sgt Gene Arden Vance Jr, 38, of Morgantown, West Virginia, a member of the 19th Special Forces Group of the West Virginia National Guard, was killed on 19 May near the southeastern village of Shkin by attackers believed to be linked to Al-Qa'eda and the Taliban. An Afghan soldier was also wounded in the incident. Since Operation Enduring Freedom began on 7 October, the number of American casualties has risen to 38. Soldiers who also lost their lives in and around Afghanistan include one Australian soldier, four Canadian soldiers, and numerous Afghans. Last Thursday enemy fighters armed with rocket-launchers and assault rifles fired on Australian Special Forces near the city of Khost. Ten of the attackers, believed to be affiliated to Al-Qa'eda and the Taliban, were killed after an American AC-130 gunship was brought in to retaliate. The US Army denied reports that it had mistakenly hit a wedding party. On Friday, a 1,000- strong force led by British Royal Marines took position in the Khost-Paktia region in a new offensive called Operation Condor that aims to destroy enemy forces in the area. In recent weeks, coalition forces have focused on the Khost and Paktia regions, believed to contain remnants of Taliban and Al- Qa'eda forces. Both regions have been a hotbed of armed clashes between rival militia groups in the area. Meanwhile, Taliban leader Mullah Mohamed Omar and Osama Bin Laden have resurfaced, if only through unsubstantiated reports in the international media. The London-based Al-Sharq Al- Awsat carried an interview on Friday with Mohamed Omar in which he said that the war in Afghanistan had entered a new phase and that Bin Laden remains alive and well. "We don't consider the battle ended in Afghanistan... The battle has begun and its fires are picking up. These fires will reach the White House, because it is the center of injustice and tyranny." The interview was reportedly conducted in Afghanistan through an aide of the Taliban leader, but neither the authenticity of the quotes nor the date of the actual interview could be verified. Yet another video was released of the elusive Bin Laden, believed to have inspired, if not masterminded, the 11 September attacks on New York and Washington. The video was obtained by The Sunday Times in Britain, reportedly from a Pakistani intelligence official. The 40-minute feature, allegedly dated to March, contains a 100-second clip of Bin Laden in camouflage addressing supporters. The Arab satellite news network Al-Jazeera said it had seen the tape three or four months earlier and dates it to October. If the tape was, in fact, just two months old, it would be the first evidence that Bin Laden is still alive. Pentagon spokeswoman Victoria Clarke said on Monday that the Al- Qa'eda terrorist network remains a threat and will prove difficult to defeat. Clarke said that Al-Qa'eda maintains cells in at least 60 countries worldwide and still has the potential and organisational capabilities to harm the United States. "Any organisation that could pull off what they pulled off on 11 September, when you think about the organisation and the planning and the resources that went into that, clearly they have some organisational capabilities that aren't going to go away overnight." On Saturday, administration officials said that proof of heightened communication among suspected Al-Qa'eda members suggests that another major attack against American and possibly European targets is being planned. Part of this information is based on an allegedly sharp increase in intelligence intercepts, a result of the boosted cooperation among allied governments in the aftermath of the 11 September attacks. Vice President Dick Cheney and National Security Adviser Condoleeza Rice made their rounds on all five major Sunday shows alerting Americans about the possibility that more attacks may be forthcoming in the near future. Cheney said on Sunday that it was "almost certain" that terrorists would target the US again. "We don't know if it's going to be tomorrow or next week or next year," he said. He added it was "not a matter of if, but when." FBI Director Robert Mueller said Monday that an attack by suicide bombers in the near future was "inevitable."