The top diplomats of Pakistan and Afghanistan were opening talks in Washington on Tuesday as US senators called for a rethink on billions of dollars sent to Islamabad for the "war on terror."
The talks come as part of a reassessment of US strategy by President Barack Obama, who plans to deploy another 17,000 US troops to Afghanistan and to put further focus on fighting extremism in Pakistan.
The foreign ministers of Afghanistan and Pakistan, which have often been at loggerheads over the conflict, will meet on Tuesday ahead of a three-way session Thursday with US Secretary of State Hillary Clinton.
Clinton "looks forward to meeting with both ministers, hearing their views, and of course sharing our views on what we believe is going on, on the ground," State Department spokesman Robert Woods said.
Ahead of the meeting, a congressional watchdog faulted a lack of a "comprehensive plan" for fighting extremism in Pakistan's Federally Administered Tribal Areas (FATA) bordering Afghanistan.
The tribal areas have never been fully under Pakistani control and are believed to be the hideout for Al-Qaeda and Taliban militants forced out of Afghanistan following the 2001 US military offensive.
The Government Accountability Office, the investigative arm of Congress, found the United States has spent 12.3 billion dollars since 2002 aiming to end the "terrorist threat" on Pakistan's border with Afghanistan.
"Despite six years of US and Pakistani government efforts, Al-Qaeda has regenerated its ability to attack the United States and continues to maintain a safe haven in Pakistan's FATA," it said.
It found that more than 70 per cent of the US assistance was military spending, mostly funding for operations. The report said it did not include covert operations.
Senator Robert Menendez, who heads the Foreign Relations subcommittee on international assistance, said the report showed US aid to Pakistan was not working.
"It's clear that the strategy in place over the past seven years must be rethought if we are to improve our security," said Menendez, a member of Obama's Democratic Party.
"I look forward to working on a policy that focuses assistance on institutions that help ensure long-term stability and minimize the threat in Pakistan," he said.
Senator Tom Harkin said the previous administration of George W Bush had "thrown billions of taxpayer dollars down a rabbit hole.
"This colossal foreign policy and national security failure is yet another legacy item of the Bush administration -- one that we will work to turn around with President Obama and the new Congress," he said.
A deputy to Pakistan's top Taliban commander on Monday declared a unilateral ceasefire in Bajaur, one of the seven federally administered tribal areas, after a months-long operation by Pakistani forces.
Islamabad says the offensive proves its commitment to crush the insurgents.
But Democratic Representative George Miller, who recently traveled to Afghanistan, said that Pakistan was not fully committed to fighting extremists, citing the role of the country's powerful intelligence agency.
"In Pakistan, we can no longer suffer the duplicity of that government in sort of fighting and not fighting and supporting and not supporting," Miller said.
He went to Afghanistan and Italy, the current chairman of the Group of Eight rich nations, with House Speaker Nancy Pelosi.
Pelosi, one of Obama's key allies, flatly rejected comparisions between Afghanistan and Vietnam, where the US-allied southern government fell after years of troop buildups by Washington.
"This is not the beginning of an escalation," Pelosi said.
Obama plans to deploy some 17,000 extra troops to Afghanistan. Currently about 70,000 foreign troops - 38,000 of them from the United States - are stationed in the country.