The Afghan government could fall apart after NATO troops pull out in 2014, particularly if presidential elections that year are fraudulent, a report by the International Crisis Group said Monday.

"There is a real risk that the regime in Kabul could collapse upon NATO's withdrawal," said Candace Rondeaux, the ICG's senior Afghanistan analyst. "The window for remedial action is closing fast."

U.S. Defense Secretary Leon Panetta has voiced frustration with Afghan President Hamid Karzai preferring to "criticize" American troops, rather than acknowledging the sacrifices they have made.

Panetta, who arrived in Peru late Friday to begin a Latin American tour, told reporters aboard the military plane taking him to Lima that Karzai should remember that more than 2,000 U.S. troops have died in Afghanistan.

Afghan President Hamid Karzai pledged Thursday that he would step down as required by the constitution at the end of his second term in 2014 and that nothing would prevent presidential elections being held.

The election coincides with the scheduled withdrawal of NATO forces from Afghanistan and questions have been raised about whether the security situation could make it impossible for the vote to go ahead.

Afghan President Hamid Karzai has sacked five provincial governors, including a key Western ally in one of the most turbulent battlegrounds of the south, officials said Thursday.

Government insiders said the move was part of efforts to reform and fight corruption, but the dismissal of Mohammad Gulab Mangal in Helmand province could ruffle British and U.S. allies who considered him an important ally against the Taliban.

A U.S.-based group urged the Afghan president Thursday to appoint independent and experienced human rights experts to seats on a national commission left vacant for nine months.

It was the second time in days that Human Rights Watch (HRW) has raised rights concerns with President Hamid Karzai, following his nomination of a cabinet minister implicated in torture to head the country's spy agency.

Australia Monday flatly rejected comments from Afghan President Hamid Karzai that a recent night-time raid which left two men dead was carried out without the approval of local authorities.

Kabul had slammed Australia over the mission, carried out in the wake of last week's killing of three Australian troops by a rogue Afghan soldier, describing it as a "unilateral military operation".

Afghan President Hamid Karzai on Wednesday announced the dismissal of his intelligence chief ahead of an imminent cabinet reshuffle involving the top security ministries.

The head of the National Directorate of Security (NDS), Rahmatullah Nabil, was dismissed as Karzai had decided that no intelligence chief could serve longer than two years, the president's office said.

U.S. Defense Secretary Leon Panetta called Afghan President Hamid Karzai on Saturday to discuss the rising number of "insider" attacks in which Afghan security forces have turned their guns on American and other coalition troops.

Spokesman George Little said Panetta encouraged Karzai to work with U.S. commanders to ensure more rigorous vetting of Afghan recruits. Little said Panetta and Karzai agreed that American and Afghan officials need to work together to address a problem that has intensified in recent days.

Eleven Afghan policemen were killed Saturday when one of their colleagues, believed to be a Taliban infiltrator, opened fire on them, officials said.

The incident in Delaram district of western Nimroz province was the latest in a series of shootings in which members of the Afghan security forces have targeted local and foreign colleagues.

Afghan President Hamid Karzai on Sunday accepted a decision by parliament to dismiss his two top security ministers but asked them to continue in a temporary capacity until they can be replaced.

Parliament's vote of no confidence in Defense Minister Abdul Rahim Wardak and Interior Minister Bismillah Mohammadi on Saturday came amid tension with Pakistan and increasing insurgent attacks as NATO prepares to withdraw its troops.