NATO Secretary General Anders Fogh Rasmussen on Monday hailed the decision by Afghan President Hamid Karzai to transfer control of security in a fresh batch of areas to local forces.

"With this decision, the Afghan security forces will be taking the lead for security for 87 percent of the Afghan population and 23 of the 34 Afghan provinces," Rasmussen said in a statement.

"This is a significant step towards our shared goal of seeing Afghans fully in charge of their own security by the end of 2014," he added, referring to the agreed date for the final handover of control. There are currently around 100,000 international troops in the country.

The latest hand-overs will take place progressively over the coming months.

The United States also welcomed the announcement.

"It is another sign of steady progress that the Government of Afghanistan has announced the fourth tranche of the transition process," US Defence Secretary Leon Panetta said in a statement.

"Going forward, our efforts in Afghanistan will continue to ensure that the Afghan people can secure and govern themselves, and to deny safe haven to al-Qaeda," he said.

NATO is aiming to train 350,000 Afghan soldiers and police by the end of 2014 to ensure stability in Afghanistan, but challenges remain. Analysts have warned the country could plunge into another large-scale civil war after the NATO-led force departs by 2015.

The Taliban were ousted from power in 2001, but have waged an 11-year insurgency against Karzai's US-backed government.

More than 1,000 Afghan soldiers died in action this year, the highest since the Taliban insurgency began, officials said on Sunday.