Washington, Sep 24 - Taliban leaders, aided by Pakistani spy agency Inter-Services Intelligence (ISI), are using their sanctuary in Pakistan to stoke a widening campaign of violence in northern and western Afghanistan, the New York Times reported.

The Taliban's leadership council, led by Mullah Muhammad Omar and operating around the southern Pakistani city of Quetta, was directly responsible for a wave of violence in once relatively placid parts of northern and western Afghanistan, the influential US daily said citing unnamed senior American military and intelligence officials.

It cited American officials as saying they believe that the Taliban leadership in Pakistan still gets support from parts of the ISI, Pakistan's military spy service.

The ISI has been the Taliban's off-again-on-again benefactor for more than a decade, and some of its senior officials see Mullah Omar as a valuable asset should the United States leave Afghanistan and the Taliban regain power.

The issue of the Taliban leadership council, or shura, in Quetta is now at the top of the Obama administration's agenda in its meetings with Pakistani officials.

At the same time, American officials face a frustrating paradox: the more the administration wrestles publicly with how substantial and lasting a military commitment to make to Afghanistan, the more the ISI is likely to strengthen bonds to the Taliban as Pakistan hedges its bets, the Times said.