Washington, Sep 27 (IANS): Ahead of Prime Minister Manmohan Singh's crucial talks with his Pakistani counterpart Nawaz Sharif in New York, where the issue of cross border terrorism is set to figure prominently, the US has expressed support for "this effort at rapprochement."

Senior Obama administration officials briefing media on a meeting between Secretary of State John Kerry and Sharif in New York Friday could not say "specifically" whether the upcoming Sunday meeting between the Indian and Pakistani Prime Ministers came up.

But "certainly we've discussed it. I mean, I've met with both the Indian and Pakistani sides over the last few days, and we're very supportive of this effort at rapprochement," said the official who cannot be identified as he was speaking on background.

During his meeting with Kerry, Sharif acknowledged that the problem of cross-border militancy and safe haven was a threat to both Pakistan and Afghanistan, the official said, according to the transcript of the briefing released by the State Department.

"It's not an exclusive problem," he said and Sharif "acknowledged that this was a challenge for Pakistan as well as Afghanistan, and he specifically said that Pakistan was never going to be at peace if Afghanistan wasn't at peace."

The issue of cross-border militancy was specifically added to US-Pakistan strategic dialogue during Kerry's recent visit to Islamabad.

"What we're trying to stress is that this is a mutual problem that both Afghanistan and Pakistan, and for that matter, India, all suffer as the result of the porousness of these borders and the infiltration of militant violent terrorist groups across them."

These groups "attack, as we know, Afghanistan, but also attack Pakistan, and the importance, therefore, of getting control of these regions and suppressing this kind of terrorist activity," the official said.

Asked if Pakistani officials had given any indication that they will make significantly greater efforts to try to prevent cross border militancy, he said the US expressed its concern about the existence of effective safe havens on both sides of the border.

Sharif "acknowledged that this was a problem, a challenge, and a threat to Pakistani security," he said.

"They are in a process at this point of seeking negotiations with the leading militant group that is targeting Pakistan, but they also are looking at alternatives, including more vigorous police and military action, should those negotiations fail," the official said.

"And I think those actions wouldn't necessarily be limited exclusively to Tehreek-e-Taliban Pakistan (TTP), particularly since the TTP operates in the same areas as many of these militant groups that target externally."