Three Pakistani troops and two civilians were killed during a clash with India over the disputed frontier in Kashmir, as Imran Khan warned of the ethnic cleansing of Muslims after Delhi revoked the region’s autonomy.

Pakistan’s military said India had opened fire over the fortified line of control killing three soldiers, before a counter attack had killed five Indian troops. India denied any of its soldiers had died and accused Pakistan of breaking a ceasefire.

The fighting came as Pakistan held a symbolic “black day” of protest to coincide with India’s Independence Day.

Mr Khan, the prime minister of Pakistan, warned there would be “radicalisation and cycles of violence” across the Muslim world if the international community ignored abuses inside Indian-administered Kashmir.

Pakistan claims ownership of the disputed territory and has reacted with fury to last week’s decision to revoke Indian-administered Kashmir’s special status.

Thursday saw newspapers print editions with black borders and politicians, including Mr Khan, replaced their social media pictures with black squares.

Mr Khan accused the Indian prime minister, Narendra Modi, of forcing Muslims out of the state of Gujarat when he was chief minister in 2002.

Likening the situation in Kashmir to the massacre of Bosniaks during the Bosnian War, Mr Khan said: “Will the world silently witness another Srebrenica-type massacre and ethnic cleansing of Muslims in Indian-occupied Kashmir? I want to warn the international community if it allows this to happen, it will have severe repercussions & reactions in the Muslim world setting off radicalisation and cycles of violence.”

Pakistan says India’s abolition of Kashmir’s self-rule move was illegal and has started a diplomatic push to try to persuade the United Nations to intervene.

Yet the country’s foreign minister has also admitted India’s trading power and Pakistan’s isolation leave Islamabad with little leverage.

Despite India imposing a strict military crackdown in what is India’s only Muslim-majority state, Pakistan’s allies in the Gulf have remained quiet.

Mr Modi told an Independence Day gathering that Kashmir’s special constitutional status had encouraged corruption and nepotism, while creating injustice for women, children and minority communities.

“Today every Indian can proudly say ‘One Nation, One Constitution’,” he said from the ramparts of the Red Fort in Delhi.

Mr Modi also used his speech to warn of an unchecked population boom in the world’s second largest nation.

He said: “It is time to accept the challenges up front… population explosion. It will bring a lot of challenges for the future generations of this country.”

“We have to think if we can do justice to the aspirations of our children. There is a need to have greater discussion and awareness on population explosion.”

The prime minister hailed an “informed section” of Indians who were already having smaller families as “playing a big role in doing good for the country”.