WASHINGTON - The White House on Tuesday welcomed increased co-operation between the United States and Pakistan against "extremists," but refused to confirm the reported arrest of a top Taliban commander. Asked at a press briefing on Tuesday whether there has been increased co-operation between US and Pakistani intelligence services, Press Secretary Robert Gibbs said, "I think we have in the course of many months seen an increase in that co-operation." "We've seen an increase in Pakistani pushback on extremists in their own country, which I think is beneficial not simply for us," he said. "The Pakistanis realised that extremist threats within (their) own borders... were threats to their own country. And I think that they've appropriately taken strong action," he said. However, he refused to confirm US media reports that the U.S. and Pakistan, working jointly, had succeeded in capturing top Taliban military commander Mullah Abdul Ghani Baradar in Karachi. Meanwhile, US State Department spokesman Gordon Duguid, who also refused to confirm Baradar's capture, told reporters at a separate briefing that the success of anti-terror co-operation presaged continued joint efforts between the two countries. "The United States and Pakistan work closely together on security issues in combating terrorism that threatens both of our societies," Duguid said. "We have had a close relationship with the Pakistani government, and I suspect that we will continue to work with them in pursuance of a policy that blunts the ability of extremist groups to attack both of our societies," the State Department spokesman said.