A top Pentagon official said Friday it would be a "tragedy" if Afghan and U.S. negotiators failed to clinch a deal allowing U.S. troops to stay in the country after 2014.

Deputy Defense Secretary Ash Carter said he told leaders in Kabul during a visit earlier this month that President Barack Obama wanted to see a bilateral security agreement wrapped up as soon as possible to provide "certainty" to commanders.

Nominations opened Monday for Afghanistan's presidential election, with a large field expected to register in the race to succeed Hamid Karzai as the U.S.-led war winds down.

The election next April 5 will mark Afghanistan's first-ever democratic transfer of power as Karzai steps aside after leading the country since the hardline Taliban regime was ousted in 2001.

A U.S. envoy on Tuesday dismissed suggestions that Washington would withdraw all troops from Afghanistan after next year, saying that both countries wanted to preserve a smaller force.

Aides to U.S. President Barack Obama earlier this year openly mulled the so-called "zero option" of a complete withdrawal from Afghanistan once U.S. troops end their combat role in 2014.

Afghan President Hamid Karzai on Wednesday ordered parliament to create a new seat for the tiny Hindu and Sikh minority after MPs snubbed their demand for separate representation.

There are an estimated 4,000 Sikhs and Hindus in Afghanistan. The community complain of discrimination, abuse and prejudice in the ultra-conservative Muslim country.

Afghan President Hamid Karzai concluded a two-day trip to Pakistan Tuesday by inviting Pakistani Prime Minister Nawaz Sharif to visit Kabul.

Karzai came to Islamabad to meet Sharif for the first time since his election in May in a bid to overcome a series of public rows that have hampered efforts to end 12 years of war in Afghanistan.

Taliban insurgents executed six Afghans working for a flagship development program funded by the World Bank in the west of the country, officials said Tuesday.

The killings were reported as Afghan President Hamid Karzai held a second day of talks in Pakistan, calling on Islamabad to help set up peace talks with the Taliban to end 12 years of war.

Afghan President Hamid Karzai asked Pakistan on Monday to help arrange peace talks between his government and Taliban insurgents, and called for a joint campaign against extremism in both countries.

Karzai was visiting Islamabad to hold his first talks with newly elected Prime Minister Nawaz Sharif, despite a series of public rows that have hampered efforts to end 12 years of war in Afghanistan.

Afghan President Hamid Karzai on Saturday called for next year's crucial election to be a U.S.-style head-to-head contest between two candidates, and named three possible runners in the wide-open race.

The April 5 election to succeed Karzai, who has ruled since the Taliban hardliners were ousted in 2001, is seen as the key test whether 12 years of massive international military and aid intervention has been worthwhile.

Afghanistan on Saturday expanded the registration of new voters to more insecure rural areas ahead of a landmark presidential election next year.

The registrations, which had already begun in cities, expanded to around 400 centers in all 34 provinces for those who have turned 18, have previously not registered or have lost their voter cards.

The Afghan president told the top U.S. military commander Monday that he was ready in principle to let American troops stay in Afghanistan beyond 2014, a month after suspending security talks.

General Martin Dempsey, the chairman of the joint chiefs of staff, is the most senior American to meet Hamid Karzai since he suspended negotiations for a long-term security pact in protest at how the Taliban opened a liaison office in Qatar.