Prime Minister Narendra Modi on Sunday gave tacit support for Donald Trump's 2020 re-election bid at the 'Howdy, Modi' event here, saying 'Abki Baar, Trump Sarkar", as the US president joined him at the mega gathering of over 50,000 Indian-Americans.

At the event, Modi and Trump clasped hands as they took the stage to a mix of drumbeats and cheers. Many spectators in the crowd of wore white T-shirts that proclaimed: "Howdy, Modi."

"We in India connected well with President Trump and with the words of candidate Trump, 'Abki Baar, Trump Sarkar', rang loud and clear," Modi said.

The slogan 'Abki Baar Trump Sarkar' was coined in 2016 by the Republican Hindu Coalition, which supported Trump and campaigned for him among the Indian-Americans.

However, by using the 2016 campaign slogan ahead of the next year's presidential elections, many consider it as Modi's apparent endorsement of Trump's candidature for the 2020 polls.

Modi's pitch will greatly help the Republican Trump in winning votes of nearly four million Indian-Americans who have traditionally voted for the Democrat Party.

Trump,73, has already announced that he will seek a second term at the White House in the general elections in 2020.

Reacting to Modi's remarks, senior Congress leader Anand Sharma in a tweet said the prime minister violated India's policy of non-interference in the domestic elections of another country.

"Mr Prime Minister, you have violated the time honoured principle of Indian foreign policy of not interfering in the domestic elections of another country. This is a singular disservice to the long-term strategic interests of India,” Sharma said.