The US has congratulated the leaders of India and Pakistan for their 'vision' in launching a bus service across the Line of Control for the first time in over 50 years.

Applauding the passengers, State Department Spokesman Richard Boucher on Thursday noted that hundreds of Kashmiris cheered along the route and that a grenade attack failed to disrupt the bus service.

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"We were glad to see those attempts to frustrate the opening (of the route) did not succeed and we were glad to see that the people who wanted this breakthrough were successful."

On Pakistan's refusal to give direct access to disgraced scientist A Q Khan to probe his nuclear proliferation network, Boucher insisted that the US regularly discussed the matter with the Pakistani government.

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Secretary of State Condoleezza Rice, he said, had occasion during her visit to Pakistan to talk to its leaders about the network and 'the need for all of us to continue to find out everything we can and pursue this information wherever it leads to'.