Asking Pakistan to clamp down on extremist groups inside its territory, a top US lawmaker has cautioned Islamabad that India would not sit idly if its soldiers or citizens were being attacked.

Joe Crowley, the chairman of the House Democratic Caucus, told PTI that the situation on the Indo-Pak border has been volatile for the past few months due to activities by Pakistan-backed militant groups, and called on the Trump administration to put more pressure on the country.

"(They) are backed by Pakistan. They (Trump administration) need to be more towards putting the pressure on Pakistan to go after LeT and other militant groups within Pakistan that are causing tensions on the India-Pakistan border," he said in response to a question.

"I think the emphasis here is that they (Pakistan) need to do more to clamp down on those violent and extremist groups within Pakistan themselves, because India will not sit by idly while it's soldiers or it's citizens are being attacked," said Crowley, a former co-Chair of the House India Caucus.

The Congressman said these issues should be handled in a bilateral manner by the two countries.