India is a "great ally" and "partner" of the US and the Trump administration will work closely with Prime Minister Narendra Modi in his second term on a range of issues, a senior State Department official said Tuesday.

State Department spokesperson Morgan Ortagus also said that Secretary of State Mike Pompeo was looking forward to having a "robust discussion" with his Indian counterpart on a wide range of issues.

The Trump administration, including President Donald Trump, Vice President Mike Pence and Pompeo, congratulated Prime Minister Modi and his Bharatiya Janata Party on the spectacular electoral victory in the Lok Sabha elections.

"We, of course, will work closely with Modi, as we have many times," Ortagus told reporters in response to a question during an off-camera news conference on Tuesday.

"We're confident in the fairness and integrity of the elections, and I think that Secretary Pompeo will have a very robust discussion on a range of issues. India is a great ally and partner of the United States," Ortagus said.

Her comment came amid a report that Pompeo may visit New Delhi next month on his way to Osaka, Japan for the G20 summit to be attended by Prime Minister Modi, US President Donald Trump and other leaders.

Meanwhile, US lawmakers and senior government officials continue to congratulate Prime Minister Modi on his electoral victory.

According to a compilation made by the Indian Embassy, more than 50 Congressmen, Senators and the senior government officials have sent congratulatory messages to Modi.

"India continues to have amazing potential and is a strong US partner. Congratulations to Narendra Modi on your success with the elections and the direction you are taking India. We look forward to seeing our partnership continue to strengthen," tweeted Indian-American politician Nikki Haley.

"Congratulations to Modi on being re-elected as Prime Minister of India," said Congressman Al Green.

"I wish peace and prosperity for India and its neighbours and look forward to seeing you at India House in my congressional district in Houston, Texas, USA," he said.