The US will be "very supportive" if conditions can be created for productive talks between India and Pakistan, a senior Trump administration official has said, underling that Washington understands New Delhi's position that "demonstrable reduction" in cross-border terrorism would create the confidence for such a dialogue.

The US welcomes the positive messages that were exchanged between Pakistan Prime Minister Imran Khan and Indian Prime Minister Narendra Modi and "how the two governments can build on what is already existing structures, whether it's the national security advisor dialogue or the DGMO channel or the people-to-people ties that have been sustained through the bus service," Alice Wells, the Principal Deputy Assistant Secretary of State for South and Central Asia told reporters during a conference call on Monday.

On August 20, Prime Minister Modi had sent a letter to Khan, conveying that New Delhi was looking for constructive and meaningful engagement with Islamabad

Khan also expressed Pakistan's willingness to re-start the stalled India-Pakistan peace process and said the two countries must engage in dialogue to resolve their differences, including on the Kashmir issue, and start trade.

Responding to a question, Wells said in general the US supports a dialogue between India and Pakistan that can reduce tensions.

"We understand and have had frequent conversations with our Indian partners on the expectations that there would be a demonstrable reduction in cross border terrorism or infiltration that will help create the confidence for a dialogue to take place," she said.

"If conditions can be created for a productive bilateral conversation, obviously we would be very supportive," Wells said.

Wells said the US had sent a two-pronged message to Pakistan: a desire to engage constructively and an emphasis on the need for Pakistan to implement its promises to fight all terrorist groups.

The India-Pakistan ties nose-dived in recent years with no bilateral talks taking place.

The ties between the two countries had strained after the terror attacks by Pakistan-based groups in 2016 and India's surgical strikes inside Pakistan-occupied Kashmir. The sentencing of alleged Indian spy Kulbhushan Jadhav to death by a military court in April last year further deteriorated bilateral ties.

The two sides often accuse each other of ceasefire violations along the Line of Control, resulting in civilian casualties.