MUMBAI, INDIA - Bal K. Thackeray, a newspaper cartoonist who became a powerful influence in this city by championing and stoking the grievances of the native population and Hindus against outsiders and Muslims, died Saturday at his home in Mumbai. He was 86.

The cause of death was a heart attack, Thackeray's doctor, Jalil Parkar, said.

Thackeray, who had described himself as an admirer of Hitler, was a formidable force in Mumbai for more than four decades even as he grew increasingly frail. Many shops, restaurants and other businesses shut down after his death was announced, as his followers prepared to mourn him and others anticipated violence by members of his right-wing and often-militant political party, the Shiv Sena. Streets out of downtown Mumbai were clogged Saturday afternoon as office workers and others rushed to get home to avoid getting caught up in any possible scuffles. Throngs of police officers were standing by and guiding traffic through busy intersections.

In New Delhi, Prime Minister Manmohan Singh appealed for "calm and sobriety during this period of loss and mourning" and canceled a dinner with opposition lawmakers to discuss a contentious session of parliament that is scheduled to start Thursday. In a statement, Singh lauded Thackeray's "strong leadership and extraordinary organizational skills."

Bal Keshav Thackeray was born on Jan. 23, 1926, in the city of Pune, about 100 miles east of Mumbai, and came of age during India's struggle for freedom from Britain. His father, Keshav Sitaram Thackeray, a journalist and activist, was said to have taken the surname because he admired the English novelist William Makepeace Thackeray. The elder Thackeray became a leader of a movement to establish the state of Maharashtra for speakers of the Marathi language, a group that would become a core constituency. Mumbai, then known as Bombay and to this day the financial hub of India, became the capital of the new state.

The younger Thackeray gained fame as a cartoonist first at the daily Free Press Journal and later at his own weekly publication, Marmik. He used his cartoons to inveigh against communists and champion the cause of the Marathi manoos, or the average Marathi citizen, who he argued was losing out to south Indians, Muslims and other outsiders. In 1966, he established the Shiv Sena, or the Army of Shiva; its mascot is a snarling tiger.