At a press conference on Tuesday, Ms Lam said the government's work on the bill had been a "total failure".

But she stopped short of saying it had been fully withdrawn, and protesters have vowed to continue mass rallies.

The bill sparked weeks of unrest in the city and the government had already suspended it indefinitely.

"But there are still lingering doubts about the government's sincerity or worries whether the government will restart the process in the Legislative Council," Ms Lam told reporters.

"So I reiterate here, there is no such plan. The bill is dead."

She had previously said the bill "will die" in 2020 when the current legislative term ends.

Protest leaders have reacted angrily to Ms Lam's latest attempt to placate them.

Bonnie Leung of the Civil Human Rights Front, which has organised demonstrations, said further protests would be held until the Hong Kong government meets five key demands. These include the full withdrawal of the bill and the dropping of charges against those detained during recent protests.

Will this be enough?

By Rupert Wingfield-Hayes, BBC News, Hong Kong

Carrie Lam's statement certainly sounds emphatic, especially in English. "The bill is dead" doesn't leave much room for quibbling. But she has stopped short of the protesters actual demand - that the widely reviled extradition bill be immediately withdrawn.

Instead she is committing herself to allowing the bill to remain in limbo until the current legislatives session ends - and then it will die by default.

The aim appears clear. The huge street protests in Hong Kong have now continued for a month. On Sunday more than 100,000 people took to the streets again. Even the leaders of pro-Beijing political parties have started to question the fitness of Ms Lam's administration, and the ineptitude of her response.

So Ms Lam has again been forced to back down, and to admit that her government's attempt to pass the extradition bill has been a "complete failure". The question now is will it be enough.

Over the past weeks, police used teargas against the protesters

"The bill is dead is a political description and it is not legislative language," Civic Party lawmaker Alvin Yeung told the BBC, adding that the bill was technically still in the process of a second reading.

"We have no idea why the chief executive refuses to adopt the word withdraw," he added.

One of the leading figures of the protest movement, student activist Joshua Wong, reiterated the demand for the bill to be "formally withdrawn" and accused Ms Lam of using wordplay to "lie to the people of Hong Kong".

Critics of the legislation argue it would undermine the territory's judicial independence and could be used to target those who speak out against the Chinese government.

Hong Kong, a former British colony, is part of China but run under a "one country, two systems" arrangement that guarantees it a level of autonomy.

It has its own judiciary and a separate legal system from mainland China.

Demonstrations continued even after the government had suspended the proposed bill in mid-June, with several protests turning violent.

On 1 July protesters forced their way into the central chamber of Hong Kong's parliament after an hours-long siege.

Many of the demonstrators are also calling for Ms Lam to step down.

In the most recent street protests, on Sunday, thousands took to the streets in an area popular with mainland Chinese tourists, in a bid to explain their concerns over the bill.