The meeting comes amid differences between the two countries over trade issues and the US threat of sanctions on Delhi if it continues to deal with Iran -- its key energy supplier -- or Russia.

Pompeo and Mattis will hold talks with Indian Foreign Minister Sushma Swaraj and Defence Minister Nirmala Sitharaman on September 6 in what is called the 2+2 dialogue, the foreign ministry spokesman said.

"The 2+2 meeting will cover a broad range of bilateral, regional and global issues of shared interest, with a view to strengthening strategic and security ties between the two countries," he said in a statement.

The talks were first meant to be held in April and then in June but they were postponed on both the occasions, triggering speculation of a possible rift between the two countries.

In 2016 the US designated India a "Major Defence Partner" with the aim of improving military cooperation and cutting red tape to ease defence deals.

But ties appear to have cooled down after US exited from the nuclear deal between Iran and world powers in May and said it would reimpose economic sanctions on the Islamic republic and its business partners by November 4.

It also warned countries including China and India, who are key buyers of Iranian oil, that they should stop purchasing crude from the country before the November deadline or face US sanctions.

The US has also threatened sanctions on any country doing business with Russia's defence and intelligence sectors.

India, the world's top defence importer, had been in talks with Russia to buy missile systems when the sanctions were announced and New Delhi has said the sanctions would not affect ties with Moscow.