At least 26 Afghan soldiers have been killed in a Taliban attack on a military base in southern Kandahar province, the defence ministry said Wednesday, the latest blow to the country's struggling security forces.

The Afghan air force said it carried out strikes backing up soldiers on the ground during the hours-long attack on the base, which began late Tuesday and ended in the early hours of Wednesday.

At least 13 soldiers were also wounded in the attack, Afghan MOD spokesman General Dawlat Waziri said. The Afghan forces “bravely resisted”, he added, killing more than 80 insurgents.

The camp was located in the remote Karzali area of Khakrez district, near the border with restive Helmand, where the Taliban hold vast swathes of territory. “We conducted multiple airstrikes killing dozens of them. Our helicopters transported wounded soldiers to hospitals in Kandahar,” said General Raziq Shirzai, the provincial air force commander.

One senior army source said up to 12 soldiers are still missing following the assault, which he described as a “very heavy attack”. The militants stole guns and vehicles as they retreated, he said.

Residents described hearing the airstrikes, and said the attack was launched by a 30-strong convoy carrying “hundreds” of Taliban who assaulted the base from multiple directions.

The militants claimed the attack via their Twitter account.

The resurgent Taliban have been ramping up their campaign against beleaguered government forces, underscoring rising insecurity in the war-torn country during the summer fighting season when the warmer weather tends to spur an increase in militant attacks.

'Shockingly high' casualties

Afghan security forces — beset by a high death toll, desertions, and non-existent “ghost soldiers” on the payroll — have been struggling to beat back the insurgents since US-led NATO troops ended their combat mission in December 2014.

Casualties among Afghan security forces soared by 35 per cent in 2016, with 6,800 soldiers and police killed, according to US watchdog SIGAR.

The insurgents have carried out more complex attacks against security forces in 2017, with SIGAR describing troop casualties in the early part of the year as “shockingly high”.

In April at least 135 soldiers are believed to have been killed on a base outside the northern city of Mazar-i-Sharif, one of the deadliest ever Taliban attacks on a military installation. Some sources put the toll as high as 200.

Meanwhile in early March gunmen disguised as doctors stormed the Sardar Daud Khan hospital — the country's largest military hospital — in Kabul, killing dozens. The Taliban have a heavy presence in Kandahar province and have launched repeated attacks on security forces there, including multiple assaults on military bases in May which killed dozens of soldiers.

A recent UN report described Kandahar, which lies on the border with Pakistan, as also one of the most dangerous places in the country for civilians.

More than 70 villagers were kidnapped by the Taliban over the weekend, officials said. Seven were found dead and some 30 returned, while Afghan police have launched a search and rescue operation for the remainder of the missing.

Afghan forces now control 59.7pc of the country, up from 57.2pc the previous quarter, according to SIGAR.But the Taliban and other insurgent groups have also seen their areas of control or influence increase slightly from about 10pc to 11.1pc.