Bangladesh, July 6 -- Donald Trump has hailed the "unmatched achievement and unlimited potential" of the US in a triumphalist address marking the country's 250th anniversary.

In a late-night campaign-style speech in Washington DC on Saturday, the US president claimed his country was "just getting started" as he vowed to take it "to new levels".

Celebrations have been marred by extreme weather, including a dangerous heatwave in recent days, and a passing storm that delayed Trump's speech. An apparent white nationalist march through the streets of Washington also caused alarm.

When he finally appeared, at 11.15pm, the president reached for a string of his favored topics, from promising a new "golden age of America" to repeating unfounde...