Pakistani President Asif Ali Zardari has called for \"serious dialogue\" with America, amid a fierce dispute over US claims that his intelligence agency has links to Islamist militants. \"Democracy always favours dialogue over confrontation,\" Zardari wrote in a Washington Post opinion piece that decried the recent \"verbal assaults\" of some US officials against Pakistan. \"It is time for the rhetoric to cool and for serious dialogue between allies to resume.\" Expressing regret over the growing tensions between the United States and Pakistan, which have struggled to overcome sharp differences to forge an alliance in the years after the September 11, 2001 attacks, Zardari said it was the militants who had gained the most from the spat. He stressed Pakistan’s role in fighting terror threats, the many lives it has lost among its security forces and civilian population and the huge cost of the anti-terror campaign. Islamabad is preparing for \"post-withdrawal realities\" after the United States removes its ground troops from Afghanistan by the end of 2014, Zardari said, recalling how Washington left Afghanistan in the 1980s after the Soviet defeat there and did little to invest in reconstruction or development. \"Whoever comes or goes, it is our coming generation that will face the firestorm. We have to live in the neighbourhood. So why is it unreasonable for us to be concerned about the immediate and long-term situation of our Western border?\" he asked. \"We struggle to hold the line against the tidal wave of extremism that surges into Pakistan each day from internationally controlled areas of Afghanistan. While we are accused of harbouring extremism, the United States is engaged in outreach and negotiations with the very same groups.\" Last week, the top US military officer Chairman of the Joint Chiefs of Staff Admiral Mike Mullen accused Pakistan of exporting violence to Afghanistan through proxies and charged that the Haqqani network, an Al Qaeda-linked group, was a \"veritable arm\" of Pakistani intelligence. US Secretary of State Hillary Clinton last week also called for better US-Pakistani ties, although she said \"serious questions\" remain about Pakistan’s support for militants. Clinton stressed in her remarks on Thursday however that the two countries \"have a lot of interests that are in common, most particularly the fight against terrorism.\"