WASHINGTON - The United States expects Pakistan's investigation into the attack on the Indian airbase in Pathankot to be "thorough and complete and as transparent as possible", a State Department spokesman said, while urging the two South Asian nations to press on with their efforts to reduce tensions between them.

"We note and we're encouraged by the fact that the Pakistani government condemned the attack and said that they would investigate," US State Department spokesman John Kirby told the daily press briefing in response to questions from Indian journalists.

Kirby said Secretary of State John Kerry spoke to Prime Minister Nawaz Sharif over telephone last week about the need to continue dialogue between the two countries.

"He (Kerry) was grateful for that time they had to talk. They talked a lot about this issue of the pressing need to stay focused on terrorism not just in Pakistan but in the region. And then he stressed that it – it’s obviously United States interest that India and Pakistan continue to look for ways to work better together to reduce the tensions – to obviously to work better together on terrorism concerns but to reduce the tensions between the two countries.

"We’re mindful of the stress that this has on local populations. We’re mindful of the insecurity that many people are faced with and dealing with every day, not just in that region but elsewhere around the world, which is why we here at the State Department remain so focused and committed to working bilaterally and multilaterally on counterterrorism challenges," Kirby added.

At the same time, reports in Indian media, quoting a "senior administration official", said that Kerry "came away believing that the Pakistani government is serious about this particular incident, serious about investigating it, serious about trying to work with partners in the region, Afghanistan specifically."

Asked whether Kerry noticed any change in Pakistan’s tone, since it had made similar promises in the context of Mumbai also, the senior administration official said: “I am not going to define it as change in tone. I think, we all recognise that more can be done, including by Pakistan. But that does not mean that we would not keep working at it.”

Meanwhile, Kirby, the State Department spokesman, refused to comment whether the US received any feedback on investigations into the attack.

“I don’t have any additional detail …..we note and we’re encouraged by the fact that the Pakistani government condemned the attack and said that they would investigate. ….our expectation is that investigation will be thorough and complete and as transparent as possible. But in terms of its progress and where they are, you’d have to talk to Pakistani authorities on it,” Kirby said.

Kirby said that, during the conversation between Sharif and Kerry, both leaders agreed to focus on war against terror in Pakistan and the entire region.

Commenting on the importance of the quadrilateral conference in Islamabad on Afghan peace process, he underscored its importance and said the US extends support for an Afghan-led, Afghan-owned peace and reconciliation process as the surest way to end the violence and to ensure long and lasting stability in Afghanistan.