At least 50 people have been killed in a 27-hour siege by Taliban forces at Kandahar airport in Afghanistan.

Eleven attackers breached the high-security complex, which also houses a joint NATO-Afghan base, on Tuesday, taking families hostage and triggering fire fights with soldiers.

The raid, which saw militants blowing themselves up among civilians before Afghan troops secured the area, is seen as the most serious attack on the complex, the largest military installation in the south of the country, in 14 years of war.

"50 of our innocent countrymen, including ten soldiers, two policemen and 38 civilians, were martyred in the attack," the defence ministry said in a statement.

It added that 37 people, including 17 soldiers and four police, were wounded.

"A group of 11 terrorists attacked a bazaar and a school in the airport complex, took up positions in the area and blew themselves among civilians."

The Taliban posted a picture on their website of the militants it said were involved in the attack. It shows 10 young men sporting trimmed beards, Kalashnikovs and identical military uniforms.

The face of one of them is obscured with blue ink for unknown reasons.

A military commander in Kandahar said radio intercepts showed some assailants were speaking Urdu, a language more common in neighbouring Pakistan, the Taliban's historic backer.

The raid coincided with Afghan President Ashraf Ghani's high-profile visit to the Pakistan capital Islamabad yesterday for the Heart of Asia conference aimed at promoting regional ties.

Mr Ghani and Pakistani prime minister Nawaz Sharif vowed their commitment to the peace process, with the US and China also offering support.

Mr Ghani's willingness to visit Afghanistan's longtime nemesis has signalled a renewed push to mend badly frayed cross-border ties, which could help jump-start peace talks with the insurgents.

Pakistan, which wields considerable influence over the Taliban, hosted a milestone first round of peace negotiations in July.

But the talks stalled when the Taliban belatedly confirmed the death of leader Mullah Omar, sparking a power struggle within the movement that lead to a rival faction splitting off last month.

The Kandahar raid came after days of fevered speculation about the fate of new Taliban leader Mullah Akhtar Mansour following reports he was critically wounded in a shootout with his own commanders in Pakistan.

The Taliban released an audio message last Saturday purportedly from Mansour, vehemently rejecting reports of any shootout as "enemy propaganda".