Police have warned marchers that they'll use tear gas even before the march organised by the Civil Human Rights Front got under way on Sunday. The warning at Percival Street came as thousands of people were gathering in Victoria Park, where the march was due to start at around 3pm. The march - from Victoria Park to Chater Road in Central - is the first march held by the group in more than four months, after earlier requests for a legal protest were repeatedly refused by the police. The front's convenor, Jimmy Sham, said they have been very cooperative with the police and were prepared to start the march early because the lawn at Victoria Park was almost full. He said it was unsatisfactory for the police to threaten to use tear gas. Sham said Hong Kong had gone through "a disastrous humanitarian crisis for months because of suppression by the police", but this would not stop the protesters from showing Hong Kong's plight to the world. Demosisto secretary general Joshua Wong said he expected hundreds of thousands of people to turn out, saying Hong Kongers have never accepted the small concessions offered by the government. He said he expects the protests to continue until at least next year. Wong also said people have grown numb to the news that police seized a pistol ahead of the march, saying that for months, police have announced that they have seized weapons before every large-scale protest. He questioned the "seizure", given the timing of the incident, just before the march. One of the marchers, Chan, a 23-year-old woman, said she believed that the police decision to approve the march would bring more peaceful protesters out - rather than radical activists. She said she felt energised because more middle-aged and older people were joining the protest. Anti-government protests are now into their sixth month, and Chan said it could take years for the protesters' five demands to be met. Police set up a strong presence guarding access to the Cross Harbour Tunnel, which was closed down last month following attacks by radical protesters.