BRUSSELS (Agencies) - Natos chief piled pressure on Pakistan on Friday to step up the fight against 'terrorists enjoying alleged safe havens in the border region with Afghanistan. But, he also called on Western governments to continue to work with Pakistan against extremists. Rasmussen said despite questions raised by the killing of Qaeda founder Osama bin Laden on Pakistani soil, he saw no alternative to co-operating with Pakistan in the war against terrorism. In his speech to the World Affairs Council in Atlanta, the head of the 28-nation Western military alliance expressed appreciation for the efforts so far by Pakistans military to fight militants in its border region with Afghanistan. Amid growing US pressure for Pakistan to take action against Al-Qaeda-linked extremists, Nato Secretary General Anders Fogh Rasmussen called for a 'positive engagement from Islamabad to ensure stability in Afghanistan. We encourage the Pakistani military and the Pakistani government to do its utmost to fight extremism and terrorism in the border region, Rasmussen said at a defence forum hosted by the European Policy Centre think tank. We should support those forces in Pakistan that realise that the real threat against the Pakistani society comes from terrorism and extremism, he added. It is really a security problem for our troops in Afghanistan that terrorists have safe havens, and thats a fact, in Pakistan, he said. We have to deal with that and its in our mutual interest to deal with that, he added. Thats a reason why we have conveyed that clear message to Pakistani authorities. But I think more could be done, Rasmussen said. The government and opposition leaders on Thursday closed ranks against increasing US pressure for action against the Al-Qaeda-linked Haqqani network, refusing to be pressured into doing more in the war on terror. In his stunning remarks, the outgoing head of the US military, Admiral Mike Mullen, last week had accused the country of 'exporting violent extremism to Afghanistan through proxies. Mullen also charged that the ISI was actively supporting the Al-Qaeda-linked Haqqani network blamed for an assault on the US embassy in Kabul this month. There are 140,000 Nato-led foreign forces in Afghanistan, some 100,000 of them from the United States, fighting a Taliban-led insurgency.