TOKYO: US Secretary of State Hillary Rodham Clinton expressed hope Sunday that Pakistan's recent reopening of Nato supply lines into Afghanistan might lead to a broader rapprochement in US-Pakistani relations after a difficult period for the reluctant allies.    

After attending a 70-nation Afghan aid conference in Tokyo, Clinton met privately with Pakistani Foreign Minister Hina Rabbani Khar to discuss reviving the US-Pakistani relationship, which has suffered a series of debilitating crises over the last year-and-a-half but is still seen as critical for the stability of South Asia.

It was their first meeting since Clinton's apology last week for the November killing of 24 Pakistani soldiers by Nato, a move that led to the end of Pakistan's seven-month blockade of the supply routes.

"We are both encouraged that we've been able to put the recent difficulties behind us so we can focus on the many challenges ahead of us," Clinton told reporters.

"We want to use the positive momentum generated by our recent agreement to take tangible steps on our many shared, core interests."

The most important of these, Clinton said, was fighting the militant groups who've used Pakistan as a rear base to attack American troops and jeopardize the future of Afghanistan.

She and Khar "focused on the necessity of defeating the terror networks that threat the stability of both Pakistan and Afghanistan, as well as the interests of the United States," Clinton said.

Pakistan's reaction in closing the border cost the US at least $700 million, as it rerouted supplies across more expensive northern routes.

The final bill may have been significantly greater.

Clinton, who joined the Pakistani minister and Afghan Foreign Minister Zalmai Rassoul for a three-way meeting later Sunday, said her discussions with Khar covered stalled Afghan reconciliation efforts. The US is counting on Pakistan to help convince the Taliban and other groups fighting the Afghan government to halt violence and enter into a political dialogue.

They spoke as well about enhancing US-Pakistani economic ties to make it a relationship defined more by trade than aid.    Still, Clinton acknowledged the lingering difficulties hindering US-Pakistani cooperation, without getting into details.    .

Clinton called it a "challenging but essential relationship."

"I have no reason to believe that it will not continue to raise hard questions for us both," she said. "But it is something that is in the interests of the United States as well as the interests of Pakistan."