US Secretary of State Hillary Clinton has said there is cross border fertilisation of terrorism in Pakistan from Afghanistan and the US would continue to press Islamabad to go after extremism in the country. In an interview to a private radio, she said Afghanistan cannot get control over its territory and defeat the Taliban if they can go across the border into Pakistan as a safe haven. Clinton added that similarly, Pakistan cannot root out the people that threaten them and their government if they can seek refuge across the border in Afghanistan. She said that is why US look at Afghanistan and Pakistan together when it comes to this fight against terrorism. <br/>