A new report claims to provide concrete evidence of direct links between Pakistan's ISI intelligence agency and the Taliban in Afghanistan.
The report, prepared by the London School of Economics, says the ISI is providing funding, training and sanctuary to the Taliban on a scale much larger than previously thought.
But the BBC reports that a spokesperson for Pakistan's military rejected the claims as part of a malicious campaign against the country.
The report's author spoke to nine Taliban field commanders in Afghanistan earlier this year.
Some of those interviewed suggest the ISI even attends meetings of the Taliban's supreme council.
They claim that by backing the insurgents, Pakistan's security service is trying to undermine Indian influence in Afghanistan.