Infamous warlord Abdul Rashid Dostum has returned to Afghanistan as the Taliban inch closer to taking control of his longtime stronghold in the north and fight for control of a string of cities elsewhere.

Ehsan Nero, a spokesman for the former army paratrooper, told AFP that Dostum arrived in Kabul on Wednesday night and was meeting senior officials to talk about security in Sheberghan, capital of Jawzjan province.

The former vice president has been in Turkey for months, where he was believed to be receiving medical treatment.

"He is waiting to meet President Ashraf Ghani," Nero said Thursday.

Dostum has overseen one of the largest militias in the north, which garnered a fearsome reputation in its fight against the Taliban in the 1990s -- along with accusations that his forces massacred thousands of insurgent prisoners of war.

A rout or retreat of his fighters would dent the Kabul government's recent hopes that militia groups could help bolster the country's overstretched military.

Fighting in Afghanistan's long-running conflict began to intensify in May, when US and other foreign forces began the final stage of a withdrawal due to be completed later this month.

The Taliban already control large portions of the countryside and are now challenging Afghan government forces in several large cities.

The European Union on Thursday condemned the Taliban's latest deadly attacks in Afghanistan and demanded "an urgent, comprehensive and permanent ceasefire".

Former Afghan vice president Abdul Rashid Dostum pictured in 2018
Former Afghan vice president Abdul Rashid Dostum pictured in 2018 AFP / NOORULLAH SHIRZADA

In a statement, EU foreign policy chief Josep Borrell and EU commissioner for aid and crisis management Janez Lenarcic accused the Taliban of breaking their promise to seek a negotiated peace.

"This senseless violence is inflicting immense suffering upon Afghan citizens and is increasing the number of internally displaced persons in search of safety and shelter," they said.

The Afghan and US militaries have stepped up air strikes against the insurgents, and the Taliban warned Wednesday that they would target senior government officials in retaliation.

The Taliban threat came after the Afghan military continued a counterattack in the southern city of Lashkar Gah, where insurgents have infiltrated several parts in numbers.

The army told the city's 200,000 people to evacuate on Tuesday.

The insurgents have taken control of vast swaths of the countryside and key border towns, taking advantage of the security vacuum left by the withdrawal of US forces.

They are now targeting cities, with fierce fighting for a week around Herat, near the western border with Iran, as well as Lashkar Gah and Kandahar in the south.

As the Taliban make battlefield gains, months of on-and-off talks between the insurgents and the Afghan government in the Qatari capital of Doha have achieved little and appear to have lost momentum.