India, Oct. 28 -- The much-anticipated peace talks between Pakistan and the Afghan Taliban in Istanbul have collapsed dramatically, diplomatic sources told NDTV, dealing a heavy blow to fragile regional peace efforts.

The breakdown has pushed Islamabad-Kabul relations to a new low and left Qatari and Turkish mediators shocked by the scale of discord and hostility witnessed behind closed doors.

According to multiple diplomatic insiders, the meeting began on a hopeful note, with most issues reportedly settled, until the talks fell apart over Pakistan's stunning public admission that it maintains a formal agreement with the United States allowing drone operations from its territory.

When Afghan negotiators sought written assurances of non...