United States Vice President JD Vance on Saturday slammed those who criticise America’s “imperfections” in a lengthy July Fourth address from the deck of an amphibious assault ship in New York.

Vance’s speech came as dozens of tall ships from more than 20 countries sailed into New York Harbour to celebrate the 250th anniversary of the signing of the Declaration of Independence on July 4, 1776.

“You will hear a couple small but loud voices today speak obsessively not of our national greatness, but of our national imperfections,” Vance said from the USS Kearsarge.

“They’ll talk about America’s sins with the anger and zeal of a brimstone preacher, but without any of the grace or forgiveness that must be present in the Christian faith,” Vance continued, adding that these critics “misunderstand the essence of America”.

As a flotilla of tall ships glided by behind him, he asked Americans to “reject the two-dimensional view of your fellow citizens and reject the two-dimensional view of your country”.

Vance’s comments echoed those of US President Donald Trump, who on Friday used even stronger language to blast “radicals and extremists” that threaten America’s identity, charging that there was “a resurgence of the communist menace in our land”.

The speeches exemplify how the major milestone in America’s history comes at a time of deep political division — but also marks a moment of celebration.

An array of military jets, including the Blue Angels, the US Navy’s flight demonstration squadron, flew over New York Harbour, some leaving red, white and blue contrails.

But a scorching heat wave across the eastern United States threatened to spoil July Fourth celebrations over the weekend. In New York City, the heat index — the apparent temperature when humidity is factored in — stood at 41°C in mid-afternoon.