MUMBAI (AFP) - Mumbai police stepped up security on Thursday to prevent any unrest as Indian firebrand politician Bal Thackeray was reported to be in critical condition at his home in the city. Large crowds of supporters gathered overnight outside the residence of the 86-year-old, who founded the right-wing Hindu party Shiv Sena and is widely accused of stoking ethnic and religious violence. “We have a lot of forces on the roads. Extra measures are being taken,” Mumbai police spokesman Nisar Tamboli told AFP. Security was particularly tight around Thackeray’s home. President Pranab Mukherjee cancelled a visit to Mumbai on Thursday.