Pakistan cancelled an upcoming conference of lawmakers from Commonwealth countries on Thursday after a feud with India over the disputed region of Kashmir, a sign of increasing tensions between the South Asian neighbors.

Islamabad called off the conference after India demanded that lawmakers from Indian-held Kashmir be included at the event, Pakistan National Assembly speaker Ayaz Sadiq said at a news conference. It had been scheduled to take place in Islamabad on Sept. 30 and 53 countries had confirmed their participation, he said.

Kashmir is a disputed region and Islamabad would not accede to India's demand, Sadiq said.

There was no immediate comment from New Delhi.

Pakistan and India have fought two wars over the Himalayan region since gaining independence from Britain in 1947. Tensions have run high in recent weeks, with the two sides trading fire across the line of control. At least nine civilians have been killed in the last week and dozens wounded.

The decision to scrap the conference came as security advisers from Pakistan and India prepared to meet in New Delhi on Sunday to discuss a range of issues aimed at easing tensions.

Also Thursday, Indian authorities detained and later released two Kashmiri separatist leaders, while a third remained under house arrest. Pakistan's foreign ministry spokesman Qazi Khalilullah said he expects India will allow national security advisor Sartaj Aziz to meet with the Kashmiri leaders during his visit to New Delhi, calling them "important stakeholders" in efforts to find a peaceful solution.