Efforts to end a tense standoff between the Indian government and a fasting anti-corruption activist appeared deadlocked Thursday, as concerns mounted over the ailing hunger striker's health. In a rare show of unity, a meeting of India's rival political parties on Wednesday ended with a joint appeal to 74-year-old Anna Hazare to end his fast, which has garnered nationwide support and put the government on the back foot. A meeting later that evening between Hazare aides and senior ministers ended in recrimination, with a senior Hazare aide saying the government had reneged on previous assurances and that negotiations were "back to square one." "It appears that there are some strong elements in the government who want to nullify the entire dialogue process," Arvind Kejriwal, a senior leader of Hazare's campaign, said Thursday. The two sides were scheduled to hold another round of talks around midday (0630 GMT) Hazare's main demand is that a government anti-corruption bill currently before parliament be withdrawn and replaced by a more stringent version drafted by himself and other civil society leaders. The government argues that such a move would undermine the parliament's constitutional authority. As Hazare's fast entered its tenth day, doctors attending him voiced fresh concerns Thursday over his health. "It is definitely worrying that 10 days have passed ... we have to keep a very close watch," said Naresh Trehan, head of the medical team that constantly monitors Hazare's vital signs. Hazare is staging his protest 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. Aides say he has lost around six kilos (13 pounds), but Hazare remains defiant, rejecting advice to go to hospital and refusing any medication. His anti-graft 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