WASHINGTON (Agencies) - Rival militant organisations on both sides of the Afghanistan-Pakistan border have increasingly been teaming up in deadly raids, in what American and Nato military and intelligence officials claimed is the insurgents latest attempt to regain the initiative after months of withering attacks from American and allied forces, reports The New York Times. New intelligence assessments from the region assert that insurgent factions now are setting aside their historic rivalries to behave like a syndicate, joining forces in ways not seen before. After one recent attack on a remote base in eastern Afghanistan, a check of the enemy dead found evidence that the fighters were from three different factions, military officials said. Officials said the unusual and expanding alliances suggest that the factions are under new military pressure. American and Nato officials say these decisions by insurgent leaders are the result of operations from American, Afghan and allied forces on one side of the border, and from the Pakistani military - and American drone strikes - on the other. One official said it was a wake-up call to find evidence, after the attack on the forward operating base, that the fighters were partisans from three factions with long histories of feuding: the Quetta Shura Taliban of Mullah Omar; the network commanded by the Haqqani family; and fighters loyal to the Hekmatyar clan. These extremist groups have begun granting one another safe passage through their areas of control in Afghanistan and Pakistan, sharing new recruits and coordinating their propaganda responses to American and allied actions on the ground, officials said. Over the past 90 days, signs of this new and advanced syndication among insurgent groups have been especially evident in two provinces of eastern Afghanistan, Kunar and Paktika. Increased cooperation among insurgent factions also is being reported inside Pakistan, where many of the extremist organisations are based or where their leaders have found haven, the Times reported.