NEW DELHI (AFP) - Indian Prime Minister Manmohan Singh and his political rivals joined forces Wednesday to appeal to social activist Anna Hazare to call off his anti-corruption hunger strike, now in its second week. But a spokesman for the ailing 74-year-old campaigner said he was holding fast to his demands, and would only terminate his fast if the government agreed to table his own tough version of an anti-corruption law. "Then Anna will end his hunger strike," Arvind Kejriwal told reporters. The joint call followed a meeting in which Singh sought help from all political parties to end the standoff, after nationwide support for Hazare caught the government on the back foot following a string of graft scandals. "We have unanimously appealed to Anna Hazare to end his fast," Sitaram Yechury, leader of the Communist Party of India, told reporters after the all-party meeting in New Delhi. The parties said in a statement they had agreed the final version of the proposed bill should provide "for a strong and effective Lokpal (anti-corruption ombudsman) which is supported by a broad national consensus". Meanwhile, Meanwhile, some 8,000 members of India's lowest-caste "dalit" community rallied in Delhi on Wednesday to protest against what they see as the elitist anti-graft campaign of fasting activist Anna Hazare. Dalit activists have challenged Hazare's campaign on several fronts, saying his efforts to force parliament into adopting stronger anti-corruption legislation poses a challenge to the Indian constitution. The constitution was drafted by the dalit icon B.R. Ambedkar and provided guarantees for the abolition of "untouchability" - although discrimination remains common against those on the lowest rung of the Hindu caste hierarchy. "It took Ambedkar two years to frame the constitution and Hazare wants to change it in a few days," said dalit social activist Anita Gautam, who was among the protesters gathered at the capital's India Gate monument. Hazare, who has not eaten since August 16, has said the version tabled by the government is too weak. Singh had on Tuesday offered a number of concessions that were also rejected by the activist's team, which sought a guarantee that the full parliament would debate his version of the legislation. "Nobody can accept such demands - parliament is sacrosanct," said the Communist Party's Yechury. However, Finance Minister Pranab Mukherjee told reporters that the all-party meeting decided that Hazare's proposed version of the anti-graft bill "would also be taken into account" in drafting the law. Hazare is staging his protest, now in its ninth day, in a large open-air venue in Delhi where tens of thousands of flag-waving supporters have gathered each day to cheer on the man who has become a symbol of national dissent. "I have just lost six kilos (13 pounds). There are concerns over my kidney. But I am deriving strength from all of you," Hazare said in a speech from his stage set above the crowd earlier in the day. Hazare is holding his fast in front of a giant photograph of India's independence icon Mahatma Gandhi, and says his protest represents a "second freedom struggle". His anti-corruption drive has brought people onto the streets of cities across the country, calling for an end to the culture of corruption that permeates all levels of Indian society. The breadth and depth of support for the campaign has shaken Singh's Congress-led government, whose own anti-corruption credentials have been tainted by a succession of multi-billion-dollar scandals. With Hazare only drinking water and refusing all food, there are mounting fears for his health among the team of doctors who constantly monitor his vital signs. "We recommended last night that for safety reasons he should be admitted to hospital... but he refused to move," the head of the medical team, Naresh Trehan, told reporters. In a letter to Hazare on Tuesday, Singh struck a pointedly conciliatory tone, saying his government shared Hazare's desire for the strongest possible anti-corruption laws. "At worst, our paths and methodologies may differ, though I do believe that even those differences have been exaggerated," he said. "I have no hesitation in saying that we need your views and actions in the service of the nation, from a robust physical condition and not in the context of frail or failing health," he added. Hazare ended a previous hunger strike after 96 hours in April when the government agreed to incorporate activists as well as politicians into the committee drafting the anti-corruption law.