WASHINGTON, Feb 6: The United States has said that Pakistan and Afghanistan have improved their cooperation to stop cross-border activities of the Taliban extremists but did not specify.

“Both Pakistan and Afghanistan have responsibilities in this regard,” said US State Department spokesman Sean McCormack when asked

at a briefing how could cross-border movement of the Taliban extremists be stopped. “They have improved their coordination.

“They have improved somewhat the effectiveness of that coordination, but there is clearly a lot more that needs to be done,” he said.

The spokesman acknowledged that despite US-led efforts to defeat the Taliban, militancy remains a problem and both Afghan and Pakistani governments were aware of the problem.

Mr McCormack said the United States had been involved with both the governments to remove their differences and improve their coordination.