Protesters remained in control of key roads in Hong Kong on Monday morning. — AFP Photo

HONG KONG — Holdout anti-government protesters remained in control of a major arterial road in Hong Kong on Monday a day after organisers said two million people flooded the streets in a historic rebuke of the city's leader.

Vast crowds marched for hours in tropical heat on Sunday calling for the resignation of chief executive Carrie Lam, who has been forced to suspend a widely loathed bill that would have allowed extraditions to the Chinese mainland.

Throngs of largely black-clad protesters snaked their way for miles through the streets to the city's parliament - with the organisers' estimate for the crowd size doubling an already record-breaking demonstration the previous on Sunday in the city of 7.3 million.

The estimate has not been independently verified but if confirmed it would be the largest demonstration in Hong Kong's history.

Police, who historically give far lower estimates for political protests, said 338,000 people turned out at the demonstration's "peak" on Sunday.

By Monday morning the crowds had dramatically dropped to just a few hundred largely young protesters occupying a major highway outside the city's parliament and some nearby streets.

Small lines of police, who had virtually disappeared the night before, were pleading with the protesters to go home but made no attempt to force them on. — AFP