The call to retreat was the most forthright and prominent yet from older democracy advocates in Hong Kong, who, while supporting the youthful protesters, had voiced deepening fears that the street occupations were angering residents and risking clashes with the police and with organized opponents.

The call from the three leaders carried more weight than those of others who have urged the demonstrators to abandon their camps, because Occupy Central has been so closely identified with the idea of using street-level civil disobedience to advance demands for democracy. The group was founded on the premise that if the Hong Kong government failed to heed demands for a fully democratic electoral system, residents should stage peaceful sit-down protests in Central, the city’s main financial district, which is filled with skyscrapers and expensive shops.

In the end, Occupy Central did not instigate the student-led protests that evolved into street camps across the city more than two months ago. But Mr. Tai endorsed the students’ sit-in at the city government’s offices, which expanded into the street occupations after a failed police operation to disperse the protesters. Now he and two co-founders of Occupy Central, Chan Kin-man and Chu Yiu-ming, have added their weight to those telling the protesters that it is time to leave.

Two weeks ago, Mr. Chan, a sociologist, published a newspaper commentary urging the protesters to retreat and focus their energies on community mobilization and education. Public opinion surveys show that growing numbers of Hong Kong residents feel that the protests have gone on too long.

Last week, the police cleared the protest camp at Mong Kok, a crowded shopping and entertainment area, and for days since, protesters have returned at night and clashed with the police. Apart from the main remaining protest site at Admiralty, protesters continue to occupy a patch of road at Causeway Bay, a retail area thronged by tourists from mainland China.