The reason for postponing the dialogue, scheduled for July 6 in Washington, was conveyed to External Affairs Minister Sushma Swaraj by Pompeo during a telephonic conversation between them on June 27, the sources said.
The North Korean issue is number one priority for the US now. Both India and the US are now working on next set of dates for the '2+2' dialogue.
Sources said the dialogue is likely to take place in the next couple of months.
They said defence and trade relations between the US and India were on track, rejecting speculation that postponement of the dialogue was reflective of a slide in bilateral ties.
Last week, the US had said that the postponement of the dialogue with India was prompted by reasons "entirely unrelated" to the bilateral relationship.
Earlier this year as well, the '2+2 dialogue' was postponed due to uncertainty over the confirmation of Pompeo as President Donald Trump's new Secretary of State.
Secretary Pompeo is scheduled to leave for North Korea tomorrow on a three-day visit to discuss that country's denuclearisation plan.
Meanwhile, the sources said Foreign Secretary Vijay Gokhale and Defence Secretary Sanjay Mitra held talks with their counterparts in Japan last week to prepare for the annual summit between Prime Minister Narendra Modi and his Japanese counterpart Shinzo Abe.