US Ambassador to India Richard Verma (right) on NDTV's Left, Right and Centre show.

It is no longer acceptable for Pakistan to distinguish between terror groups that attack them and those that attack India, US Ambassador to India Richard Verma has said.In an exclusive interview to NDTV, Ambassador Verma said, "More needs to be done, some action has been taken. This distinction between different terror groups is not acceptable and we have to use the leverage we have to make sure effective action is taken across the board against any group that threatens free people."Asked about America's continued military and other aid to Islamabad, Mr Verma said there was frustration that Pakistan wasn't doing enough, which is why aid had been scaled down."Obviously there is frustration of not taking sufficient action on the Pakistani side. Congress has imposed a number of restrictions as they've been frustrated by the inability to go after groups like Haqqani and the LeT (Lashkar-e-Taiba) which have threatened and brought great harm to Americans in Afghanistan."Asked about whether anything would be different post the Pathankot terror attack, in which six Pakistani terrorists killed seven military personnel at the air force base, the Ambassador said "We have to see and we have to keep up the pressure. We have to engage with the Pakistanis to do more to crack down on these groups."The envoy also came out in strong support for Delhi's Odd-Even plan for traffic, saying there was no plan by the US embassy to scale down the tenure of diplomatic postings as a result of high pollution levels."It's about shared sacrifice. It's one thing to just point and complain at the policy makers and it's quite another to try and come up with solutions and we wanted to be part of the solution. It wasn't easy for a lot of our local support staff just like it wasn't easy for a lot of people across Delhi, but I think it's such a pressing issue and it really could stifle India's growth," he said.Commenting on the US election campaign and the anti-Muslim and anti-immigrant comments of Donald Trump, the envoy was highly critical of the Republican candidate."Those comments you mentioned that Mr Trump uttered, have been widely condemned across the political spectrum," he said, adding, "I started working in politics at the age of 18 in the House of Representatives and what really excited me was the politics that lifted people up and brought people together and gave people hope and unified the county. That's the kind of politics that attracted my parents and millions around the world to the US."Asked what explains Mr Trump's popularity, he said, "I think there is still a lot of economic insecurity, and sometimes they seize upon people on the lowest common denominator in politics and seize upon fear and anger instead of hope and promise."