Video report by ITV News Correspondent Debi Edwards
The Hong Kong government has apologised for its handling of proposed legislation, but protesters are calling on the city's leader to step down.
Demonstrators, mostly clad in black, jammed the city's streets on Sunday in vehement show of opposition to the bill, despite its suspension on Saturday.
Organisers said nearly two million people turned out to the protest, but police said 338,000 people were counted on the designated protest route during the march's "peak period".
Hong Kong's chief executive, Carrie Lam, suspended her effort to force the bill through, which would allow some suspects to be sent for trial in mainland China.
Many fear it signals expanding control from Beijing in the former British colony.
However the move did not appease Hong Kong residents angered over the plan who see it as one of many steps chipping away at the city's freedoms and legal autonomy.
The marchers are demanding that the extradition bill is completely scrapped, not just suspended, and for Ms Lam to resign.
Well after dark crowds gathered outside the police headquarters and chief executive Ms Lam's office.
She issued an apology to the protesters and said the government "understands that these views have been made out of love and care for Hong Kong".
"The chief executive apologised to the people of Hong Kong for this and pledged to adopt a most sincere and humble attitude to accept criticisms and make improvements in serving the public," a statement said.
Opponents worry the law could be used to send criminal suspects to China to potentially face vague political charges, possible torture and unfair trials.
The conflict, which slipped into unusually violent clashes with police last week, is one of the toughest tests of the territory's special status since China took control from Britain in a 1997 handover.
Meanwhile, a steady stream of mourners were stopping by a makeshift memorial to lay flowers and pray for a man who fell to his death on Saturday after hanging a protest banner.
The man slipped from the grasp of rescuers after clinging for a time to scaffolding outside a shopping centre. He missed a big cushion set up to capture him, and was declared dead at a nearby hospital.
The banner read “Make Love, No Shoot” and “No Extradition to China”.
Pro-democracy activists are calling for a general strike on Monday, despite the suspension of the bill.
The demonstrators carried banners demanding that Ms Lam steps down and repeatedly broke into chants.
"Our demands are simple," said bank worker John Chow as he marched with a group of friends.
"Carrie Lam must leave office, the extradition law must be withdrawn and the police must apologise for using extreme violence against their own people. And we will continue."
What are the protests all about? Natalia Jorquera explains
Walking slowly and shouting "withdraw" and "resign," the crowd filled a wide thoroughfare and side streets paralleling the waterfront of Victoria Harbor as tourists and shoppers who drive much of the Asian financial hub's economy looked on.
In her statement on Saturday, Ms Lam made it clear she still supports the bill and the pause is to allow order to be restored in the city.
Some labour unions, teachers associations and other groups are planning boycotts of work and classes.
“We encourage all the public to carry on the campaign,” said Bonny Leung and other leaders of the pro-democracy Civil Human Rights Front.
The communist government in Beijing issued multiple statements backing Ms Lam’s decision, which she announced in a news conference on Saturday.
The battle over legislation has evolved into Hong Kong’s toughest political test since the Communist Party-ruled mainland took control in 1997 with a promise not to interfere with the city’s civil liberties and courts.
A week earlier up to a million rallied in protest, and demonstrations on Wednesday turned violent, with dozens injured as police fought back with tear gas, rubber bullets and other forceful measures.
Ms Lam has said the extradition legislation is needed for Hong Kong to uphold justice, meet its international obligations and not become a magnet for fugitives.
The proposed bill would expand the scope of criminal suspect transfers to include Taiwan, Macau and mainland China.
China had been excluded from Hong Kong’s extradition agreements because of concerns over its judicial independence and human rights record.
Speaking to reporters after announcing her decision, Ms Lam sidestepped questions over whether she should quit. She insisted she was not withdrawing the proposed amendment and defended the police.
But she said she was suspending the bill indefinitely. It was time, she said, “for responsible government to restore as quickly as possible this calmness in society”.
“I want to stress that the government is adopting an open mind,” she said. “We have no intention to set a deadline for this work.”