Hong Kong's democracy protests have stoked fears of retribution from China, but observers say the city is simply too valuable to punish and sideline, even as it faces a long-term challenge from mainland rival Shanghai.

Demonstrators, sometimes numbering in the tens of thousands, have taken to Hong Kong's streets over the past week to demand free elections for the city's leader in 2017, a display of civil disobedience initially met with tear gas from riot police and later attacks by unidentified men.

Pro-democracy lawmakers accused Hong Kong's leaders of trying to evade a public backlash over mass protests in the city after they canceled the opening session of the de facto parliament Tuesday.

The pro-Beijing speaker of the house said concern for safety was behind the postponement of the first sitting of the Legislative Council which was due to take place Wednesday.

Small groups of pro-democracy demonstrators remained on Hong Kong's streets Tuesday after protest leaders agreed to talks with the government and some students returned to school for exams.

Talks between the government and student leaders are progressing at a snail's pace, although even protest leaders are now acutely worried that further disruption could alienate supporters.

The official mouthpiece of China's ruling Communist Party on Monday slammed pro-democracy demonstrations in Hong Kong as "driving democracy backwards", while state media continued to emphasize disruption caused by the protests.

The People's Daily renewed its criticism in three separate articles on the movement, primarily led by students and the Occupy Central group, which in recent days has seen tens of thousands of protesters bring parts of the global financial hub to a standstill.

Exhausted Hong Kong demonstrators debated the next step in their pro-democracy campaign Monday as their numbers dwindled after a week of rallies, and the city returned to work despite road closures and traffic gridlock.

The protests for free elections that had drawn tens of thousands evaporated Sunday night in the face of a warning from Hong Kong's embattled leader Leung Chun-ying to disperse and allow government offices to reopen.

Pro-democracy demonstrators in Hong Kong on Sunday announced a partial withdrawal from some protest sites, but others vowed to stay on ahead of a deadline to clear the streets.

Occupy Central, one of the groups organizing the protests, said protesters would leave a secondary site to reinforce the main demonstration area and would allow access to a blockaded road near the government's downtown headquarters.

Women pro-democracy protesters in Hong Kong are being targeted with sexual assaults and harassment, demonstrators and an international human rights group said as violence broke out in two of the city's busiest shopping districts.

Amnesty International accused the police of "failing in their duty" to protect demonstrators on Friday evening, saying officers "stood by and did nothing" when counter demonstrators and suspected triad members clashed with activists at protest sites in Mongkok and Causeway Bay.

Tens of thousands of pro-democracy protesters held a peace rally in central Hong Kong in defiance of recent attacks against their ranks, as students early Sunday re-opened the door for talks with government over their political reform demands.

Hong Kong's main student union, which had called off the negotiations saying police failed to act over the violent clashes, said it would meet with the government on the condition it responded over the police handling of the ugly scenes Friday.

Hong Kong student leaders on Friday called off talks with the government aimed at bringing an end to mass pro-democracy demonstrations that have paralyzed the city, after violent clashes broke out with opposing crowds at their protest camps.

Hong Kong's main student union walked away from negotiations after angry opponents, some waving Chinese flags, began tearing down their tents and barricades in what activists said was orchestrated violence by paid thugs from "triad" criminal gangs.

The official mouthpiece of China's ruling Communist party said Friday that authorities will not make concessions to pro-democracy protesters in Hong Kong and that their cause is "doomed to fail".

Students whose peaceful protests have paralyzed parts of the global financial hub have agreed to hold talks with the government while vowing to continue their occupation, as the city's under-fire leader refused to stand down.