The army's top commanders met in the garrison city of Rawalpindi to discuss the move by India, which is also set to exacerbate the long-running bloody rebellion in Kashmir.

"Pakistan Army firmly stands by the Kashmiris in their just struggle to the very end. We are prepared and shall go to any extent to fulfil our obligations in this regard," General Qamar Javed Bajwa said, in a tweet sent by a military spokesman after the meeting.

Spokesman Major General Asif Ghafoor said commanders "fully supported" the civilian government's rejection of India's move.

"Pakistan never recognised the sham Indian efforts to legalise its occupation" of the disputed mountainous region, he added.

On Tuesday, an estimated 500 people demonstrated in Muzaffarabad, the largest city in Pakistani-held Kashmir, with more protests expected in major cities across the country.

Pakistani lawmakers also began a joint-session of parliament to discuss a possible response to Delhi's move.

Indian Prime Minister Narendra Modi's Hindu-nationalist party on Monday rushed through a presidential decree to scrap the special status granted to the Indian-ruled part of Kashmir from India's constitution.

It also moved a bill proposing the Indian-administered part of the Himalayan region be divided into two regions directly ruled by New Delhi.

The breathtaking Himalayan region of Kashmir has been disputed by India and Pakistan since independence in 1947. They have fought two of their three wars over the former principality.

Earlier this year they came close to war yet again, after a militant attack in Indian-held Kashmir in February was claimed by a group based in Pakistan, igniting tit-for-tat air strikes.

For three decades the Indian-administered part has been in the grip of an insurgency that has left tens of thousands dead.

Armed Kashmiri rebels and many residents have fought for the Muslim majority region's independence or to join neighbour Pakistan.

Ahead of the announcements, tens of thousands of extra Indian troops were deployed in the territory, and a security lockdown was imposed overnight Sunday. All telecommunications have been cut there since.

Editorials and social media in Pakistan were buzzing Tuesday over Modi's decision, with the English daily Dawn running a large headline on its front page reading: "New Delhi sheds fig leaf, robs held Kashmir of special status".