India's crackdown on protests and dissent in Kashmir will drive more of the world's Muslims into extremism, Pakistani Prime Minister Imran Khan said during a fiery speech on Friday, in the part of the disputed territory administered by Pakistan.

India revoked the special status of its portion of Kashmir, known as Jammu and Kashmir, on August 5 and moved to quell unrest by clamping down on communications and freedom of movement. Authorities in Indian Kashmir have arrested nearly 4,000 people since then, government data seen by Reuters showed.

"When atrocities get to their peak, people would prefer that death is better than this insulting life," Khan said at a rally of several thousand people in Muzaffarabad, the capital of Azad Kashmir.

"I want to tell India that, by detaining thousands of people, you are pushing people into extremism," he said.

"People will rise against India, and it is not just about Indian Muslims, there are 1.25 billion Muslims around the world. They all are watching this."

Khan said he would attend the United Nations General Assembly in New York next week to defend Kashmiris' cause.

He urged people in Azad Kashmir not to approach the Line of Control that separates it from Indian-controlled Kashmir, but to wait for him to press their case in New York.

On Tuesday, Pakistan's foreign minister told the United Nations human rights forum that India's military presence in Kashmir raised the spectre of genocide.

The Delhi government has said its abolition of Kashmir's special status, which had allowed it to write many of its own laws, is meant to help to combat terrorism and to boost the region's economic development.

About two-thirds of the population of Jammu and Kashmir is Muslim, while India has an overall Hindu majority.

India rules the heavily populated Kashmir Valley and the Hindu-dominated region around Jammu city, while Pakistan controls a wedge of territory in the west. China holds a thinly populated high-altitude area in the north.