KABUL - Nato’s new chief Jens Stoltenberg pledged Thursday that Afghanistan would not be abandoned when the alliance’s combat mission ends next month after 13 years of fighting against resilient Taliban insurgents.

Nato’s International Security Assistance Force (ISAF) will finish operations at the end of the year and be replaced by a far smaller training and support mission named “Resolute Support”. But Afghanistan’s stability could be at risk without international troops on the battlefield as the country’s security forces endure huge casualties in the bloody struggle to thwart the Taliban.

“Next year, we will open a new chapter. The future of Afghanistan will be in Afghan hands, but our support will continue,” Secretary General Stoltenberg said on his first visit to Kabul since taking office last month. “We will start a new mission to train, advise and assist Afghan forces. We will also continue our financial support.” ISAF troop numbers peaked at 130,000 in 2010, but now stand at less than 34,000.

Only about 12,500 soldiers, most of them from the United States, will remain into 2015 to continue training the Afghan forces, who have already taken over most of the fighting.

This year alone more than 4,600 Afghan soldiers and police have been killed in combat, Lieutenant General Joseph Anderson, the number two ranking US officer in Afghanistan, revealed Wednesday.

“Those numbers are not sustainable in the long term,” he said, adding the Afghan army and police were “holding their ground against the enemy.”

Nato’s US-led coalition has suffered about 3,450 casualties in Afghanistan since 2001, according to the independent icasualties website.

President Ashraf Ghani, who came to power in September, said Afghan forces were ready to accept full responsibility, but that Nato’s support mission would aid the search for peace after decades of conflict.

“Our security forces will bravely defend the country. Our financial resources are unfortunately are not enough, but Nato’s commitment reassures us,” he said at a joint press conference after talks with Stoltenberg.

“I completely think it is appropriate for the Nato force to leave Afghanistan.

“This does not mean the world will abandon us. The Nato mission will change to support and equipment.”

Ghani had already begun to reset ties with the US and Nato by signing a long-delayed agreement allowing international troops to remain beyond December.

The deal - signed on Ghani’s first day in power - was a major cause of friction between Washington and former president Hamid Karzai.

The US-led combat mission began in 2001 with the ousting of the Taliban regime that sheltered Al-Qaeda leaders behind the 9/11 attacks on New York and Washington.

A prolonged dispute over June’s election results triggered fears that Afghanistan could be heading for renewed ethnic conflict as Ghani and his rival Abdullah Abdullah both claimed to have won the fraud-mired vote.

The two eventually agreed to form a unity government, though the coalition is likely to be uneasy.

Pakistan’s powerful army chief General Raheel Sharif was also in the Afghan capital on Thursday for talks with Ghani.

Relations between the neighbouring countries have been strained amid accusations from both governments that militants are allowed to shelter on either side of the border.

A Pakistan army spokesman described the meeting as full of “good will and positivity”.