Islamabad, Aug 2 (IANS): A leading Pakistani newspaper on Wednesday urged Islamabad and Kabul to jointly fight the Islamic State terrorist group.

With the IS now facing setbacks in Iraq and Syria, it can be expected to start taking roots in Afghanistan and Pakistan as well, the Dawn said in an editorial.

"Afghanistan - long suffering from conflict - seems to be an ideal location for the self-proclaimed ‘Caliphate' to put down roots," it said.

It quoted American military officials as saying there may be around 1,000 IS fighters active in Afghanistan.

"Due to a long, porous border and a complicated relationship, often Afghanistan's militancy problems spill over into Pakistan; the case of IS is no different," it said.

"Transnational militancy is a nebulous phenomenon; it does not recognise borders or national sovereignty.

"That is why it is imperative that Pakistan and Afghanistan work together to neutralise the threat of IS in both countries.

"This may be difficult to achieve, given the often tense relations that prevail between Islamabad and Kabul.

"But as IS and militants sympathetic to its ideology have shown elsewhere, if a vacuum is left - as was the case in Syria and Iraq - IS will move in very quickly to fill it.

"That is something neither Pakistan nor Afghanistan can afford. Therefore, a joint policy to counter IS is the only way forward," the Dawn said.