By M Ilyas Khan, BBC News, Islamabad

The Pakistani prime ministers adviser on foreign affairs has indicated in a talk at Washingtons Council on Foreign Relations (CFR) that the leadership of Afghan Taliban is living in Pakistan.

For many such a disclosure has been an open secret for years, but one which Pakistans powerful military refrained from talking about.

So what did he say?

Answering a question about the extent to which Pakistan could encourage or pressure the Taliban to negotiate peace with Kabul, Sartaj Aziz said: "We have some influence on them because their leadership is in Pakistan, and they get some medical facilities, their families are here. So we can use those levers to pressurise them to say, come to the table."

He made clear in his CFR talk, however, that Pakistan could not negotiate with the Taliban on behalf of the Afghan government.

"It is for the Afghan Taliban and the Afghan government to negotiate," he said.

How big a deal is that?

His comments are seen by analysts as the most candid admission ever by a Pakistani official that Afghan insurgents enjoy sanctuary in Pakistan.

In the past, Pakistan has denied it had any influence over the Taliban, or that they had any havens on Pakistani soil except in the semi-autonomous tribal region on the border with Afghanistan.

Mr Azizs remarks come in the wake of a 20-month military operation in the area, which the Pakistani army says has cleared the country of all militant strongholds.

How will it affect talks with the Taliban?

Mr Aziz was in Washington this week to lead his team in the sixth round of US-Pakistan strategic dialogue, which included exchanges over peace in Afghanistan and the role Pakistan could play in bringing the Taliban to the dialogue table.

Since December, Pakistan has been a member of a quadrilateral co-ordination group which also includes Afghanistan, the US and China.

During the past two months, the group has held four meetings to develop a roadmap for Afghan peace negotiations.

During his talk at CFR, Mr Aziz indicated that a meeting between Taliban and the Afghan government may take place in the coming 10-15 days.

What has been the response in Pakistan?

Pakistans foreign office has taken a cautious view of the matter.

On Thursday, a foreign office spokesman declined to offer any reaction to Mr Azizs remarks, saying "we do not make any comment on [political leaders statements]. He [Mr Aziz] has said what he had to say".

But for most Pakistan-watchers around the world, his remarks do not come as a surprise.

What evidence is there that the Afghan Taliban are in Pakistan?

Pakistan has long been accused by international circles of protecting the Afghan Taliban so as to use them as a proxies in Afghanistan with an aim to curtail Indian influence in its western neighbourhood.

This has caused a near-permanent state of mistrust between Pakistan and Afghanistan on the one hand, and between Pakistan and India on the other. While the two neighbours have been blaming Pakistan for using militancy as a tool of state policy, Islamabad has continued to deny this.

This has caused disruptions in the Afghan peace talks, says Tahir Khan, a former BBC Pashto correspondent in Islamabad who covers Afghanistan.

He recalls the episode in August 2015 when a sceptical Kabul establishment leaked the news of Taliban supreme leader Mullah Omars death to media, casting aspersions over the effectiveness of Pakistan-brokered talks.

The revelation, which was followed by reports that Mullah Omar had spent time in a hospital in the Pakistani city of Karachi, embarrassed Pakistan and caused rifts within the Taliban ranks, some of whom blamed the movements current leadership of "cunningly hiding" the news for almost three years, allegedly at the behest of the Pakistani military.

Dont forget the murder at the bakery

There have been other instances to show that Taliban leaders have been operating out of Pakistan.

A more prominent example is the 2013 assassination of a Haqqani Network leader, Nasiruddin Haqqani, in the Pakistani capital, Islamabad.

It was also widely known that the Taliban delegates who attended the first round of talks with Afghan officials in the Pakistani hill resort of Murree in July 2015 did not arrive from abroad, but travelled from destinations within Pakistan.

Ismail Khan, the resident editor of Dawn newspaper in Peshawar, says Mr Azizs remarks have only helped remove an anomaly in the Pakistani position.

"The factor of credible deniability is simply not there anymore, and Mr Aziz seems to have made this clear," he says.

How will Mr Azizs remarks go down with the military?

Though a democratic republic, Pakistan has for a better part of its life been a country where all issues central to foreign policy, defence and internal security have remained an exclusive domain of the military.

The Taliban, and other militant networks operating in the region, fall within that domain.

So Mr Azizs remarks have raised questions about whether his views reflect those of the military.

The media wing of the military, which many in Pakistan consider to have become extremely vocal since the recent army chief, Gen Raheel Sharif, took over in November 2013, has been quiet so far.

Ismail Khan of Dawn newspaper believes the military may not have any issues with Mr Azizs remarks, given that he has only stated the obvious.

Former BBC correspondent Tahir Khan thinks if the military has any reservations, we will soon see attempts by the political establishment to clarify Mr Azizs remarks.

Or there may be a deafening silence from the military, like when the news of Mullah Omars death was revealed by the Afghan officials.

How will the Taliban react?

The Afghan Taliban have not reacted to Mr Azizs remarks yet.

Tahir Khan believes the admission that their leadership is based in Pakistan may put moral pressure on the Taliban to abide by the dictates of the Pakistani establishment.

This is because it endorses the view of Afghan insurgents opposed to the current Taliban chief, Mullah Akhtar Mansoor, that he is a lackey of Pakistan.

There are reports that several among the Taliban leadership ranks are not prepared to strike a deal with Kabul on Pakistani terms.

If Mullah Mansoor continues on a divergent path to that of Pakistan, he will risk losing credibility both with Pakistan and his opponents.