Occupy Central organisers found themselves in a damned-if-you-do, damned-if-you-don't dilemma after they acceded yesterday to calls to bring forward a mass sit-in - but then met with accusations the move "hijacked" an ongoing student campaign. The long-awaited start of Occupy's first blockade of Central streets hit a stumbling block when many attending a Federation of Students rally in Admiralty left right after Benny Tai Yiu-ting's sudden launch of the civil disobedience action at 1.45am. Both Occupy and federation leaders had meant to ride the wave of democracy fervour at the Tim Mei Avenue rally outside the government headquarters that ended five days of class boycotts. But the move took flocks of protesters by surprise. They said their overnight stay was meant to back students who were arrested for charging into Civic Square at the headquarters. A group of City University students asked the federation to clarify the event they were taking part in was not "Occupy Central". "We are here to support the federation and the class boycotts. Not everyone here wants to get arrested by police," Karma Kong, 25, said. "[Occupy] has hijacked this movement." It was understood Tai and his Occupy co-organisers reached a consensus with the federation at a Saturday night meeting in which they agreed the time for the planned sit-in had arrived. Watch: Co-organiser Benny Tai declares start of Occupy's civil disobedience action "The public's reaction is out of my expectations," Tai said. "Our message might have been unclear, giving the public an impression [of us hijacking the students' movement]." Occupy's democracy showdown had been expected to begin on Wednesday to campaign against Beijing's restrictive framework for the 2017 chief executive election. Core Occupy member Shiu Ka-chun said: "Many civil groups had urged us to stage the sit-in earlier to protect the students [who had been pepper-sprayed]. But after we did so, these groups of people did not try to defend us when others made the 'hijack' accusations." The campaign appeared vulnerable after Tai's announcement, Shiu said. "The three co-organisers did not dare to lead the rally on stage ... People were unhappy we failed to persuade the protesters stay." Federation spokeswoman Yvonne Leung Lai-kwok rejected the criticism. "It is not the right time to ask who is leading the movement. Every Hongkonger should come forward … to safeguard Hong Kong." Political scientist Ma Ngok agreed the reaction was "unexpected". "We all thought we were here for the same cause - to fight for democracy," he said. Despite the criticism, many did stay - and more joined in after dawn broke. "We are not staying for Occupy or for the students," a social work student said. "We are here for ourselves and Hong Kong - our home."