Washington: US has asked Pakistan President Pervez Musharraf to fulfil his pledge to end infiltration of terrorists from Pakistan and remove "fundamental differences" with India by following through such promise with "concerted and pro-active" actions.

"President Musharraf has repeatedly committed to ending permanently support for infiltration from his country. Pakistan needs to hold to this pledge in order to begin resolving the immediate crisis and to remove more fundamental differences with India," assistant secretary of state for South Asia, Christina Rocca said while addressing the American Enterprise Institute, a major think tank.

"We look to Islamabad to follow through on this commitment in a concerted and pro- active manner," she added.

The most difficult task US faces in South Asia was that of defusing Indo-Pakistan tensions "which pose the greatest obstacle to overall progress in the region", Rocca, who returned earlier this week from her tour of South Asia, said.

India and Pakistan will not be able to reap the benefits of regional economic development and co-operation unless they build a more stable relationship, she said.

"Ongoing conflict between India and Pakistan not only risks dangerous escalation, but also limits the ability of both countries to seize opportunities to better the lives of their own people," she said.

PTI