Hardline Hindus have ransacked the office of an Indian news magazine in protest over an article that described their leader as a villain, police say.
Police are investigating the attack
An accompanying Outlook cartoon showed Shiv Sena leader Bal Thackeray dressed as German war leader Adolf Hitler.
Some 12 members of the Shiv Sena party attacked the offices of the Outlook magazine in the financial centre of Mumbai (Bombay), police said.
They smashed windows and damaged computers but no-one was hurt.
Mr Thackeray has spoken approvingly of Hitler in the past.
Outlook editor Vinod Mehta said that six men - who said they belonged to the Hindu nationalist party - carried out the attack.
Bal Thackeray is revered by many Shiv Sena supporters
"It's a clear and blatant attack on the freedom of the press. It was an ugly scene. The men broke windows and intimidated and threatened staff," Mr Mehta told the AP news agency.
He said that the chief minister of Maharashtra, Vilasrao Deshmukh, has promised to take action against the attackers.
"The staff is traumatised because these guys threatened to come back. We have demanded police action, not just against these foot soldiers but against the person who masterminded the attack," he said.
The magazine quoted speeches made by Mr Thackeray against India's minority Muslim community to justify its description of him as a villain in its latest Independence Day issue.
Other people on the list included Nathuram Godse, the assassin of Indian independence leader Mohandas Gandhi; Jarnail Singh Bhindranwale, a Sikh separatist leader; underworld leader Dawood Ibrahim; and Narendra Modi, a right-wing leader accused of ignoring mob violence in the Western state of Gujarat in 2002.
Mumbai-based Shiv Sena leader Vinayak Raut defended the office attack, but said his party was investigating to see who was responsible.
"The cartoon is wrong. Some Shiv Sainiks may have reacted to it. But we are still getting information to see if the men were actually from Shiv Sena," he told AP.
Police said they were investigating the complaint.