WASHINGTON: The Trump administration needs to place "greater pressure" on Pakistan to make it realise that its "longstanding strategy" of using terror proxies in war-torn Afghanistan is both costly and ineffective, according to a top US expert.Pakistan has not deviated from its basic commitment to supporting its favoured proxies in Afghanistan, Daniel Markey from Global Policy Program at Johns Hopkins School of Advanced International Studies said in an op-ed in The Cipher Brief, a global security news platform."As for placing greater pressure on Pakistan to change course, the United State needs to demonstrate that Pakistan's longstanding strategy of using terrorist proxies is both costly and ineffective," he said on Thursday."Sadly, that message was never delivered convincingly by the George W Bush or Obama administrations," Markey said as he recommend that an escalation of US military action directed at Taliban leadership with the principal aim of compelling negotiations is now probably Washington's best hope for anything other than a very long Afghan stalemate.Or worse, another escalation of violence that could collapse the Kabul government and prompt a humiliating American withdrawal, he said."Pakistani leaders would prefer that Washington accept their concerns as legitimate and lend support to a brokered peace process for Afghanistan that would deliver a significant share of national power to pro-Pakistan groups and demonstrate Islamabad's dominant regional role," he wrote.According to Markey, Washington has succeeded on multiple occasions in getting Pakistan to bring Taliban negotiators to the table."The trouble is that these negotiators — and their Pakistani patrons — have not shown themselves to be serious when it comes to seeking a negotiated settlement," he said."To the contrary, US officials perceive that the Taliban have used talks as a stalling tactic and a pretext for other diplomatic games intended to confer greater international legitimacy on the insurgency and to call into question that of the Afghan government in Kabul," the US expert said.Pakistan's Ambassador to the US Aizaz Ahmad Chaudhry told The Cipher Brief that it is "totally an absurd suggestion" that Pakistan's Inter-Services Intelligence agency maintains close ties to the Taliban and the Haqqani network."It does not even call for a comment. Pakistan's intelligence agency and our law enforcement authorities have played a critical role in decimating al-Qaeda and other terror networks in the region," Chaudhry said.He said that building mutual trust between Pakistan and the US would be important to promote peace in the region."The history tells us that when our two countries collaborated with mutual cooperation, positive results were achieved, for example, in the fight against al-Qaeda. That is why we believe that trust and mutual respect should constitute the key pillar of Pakistan-US relationship as both the countries genuinely desire peace and stability in the region," he said.However, top American counter-terrorism experts have refuted the Pakistani diplomat's claims.Bruce Riedel, director of the Intelligence Project at the Brookings Institution , said the Haqqani network still operates as an extension of the Pakistani intelligence services."They receive safe havens and receive sanctuary from the Pakistani intelligence service which often cooperates in the planning of operations with the Haqqani network, including planning of operations against American targets," he said.Bennett Seftel, deputy director of analysis at The Cipher Brief, said that many in the US have been dismayed by the Pakistani government's lack of willpower to force the Taliban to the negotiating table and end the ongoing military stalemate in Afghanistan."A sign of any new approach by the US may be revealed in the next few weeks when the Pentagon is expected to complete its review of US policy in Afghanistan and the region," Seftel wrote in the report.