Two of Afghanistan's most notorious regional strongmen fled on Saturday as the northern city of Mazar-i-Sharif fell to the Taliban and security forces abandoned the city in a headlong rush up the highway to the safety of neighbouring Uzbekistan.

Atta Mohammad Noor, the former governor of Balkh province and the ethnic Uzbek leader Abdul Rashid Dostum have been involved in wars in Afghanistan since the days of the Soviet invasion and had been among the Taliban's fiercest enemies.

Noor, who had been commanding local militia forces when Mazar-i-Sharif fell to the Taliban, said both he and Dostum were safe and blamed the fall of the city on a "conspiracy".

Taliban forces entered the city virtually unopposed as security forces escaped up the highway to Uzbekistan, provincial officials said. Unverified pictures on social media showed Afghan army vehicles and men in uniforms crowding the iron bridge at the Hairatan crossing.

"Despite our firm resistance, sadly, all the government and the #ANDSF equipments were handed over to the #Taliban as a result of a big organised & cowardly plot," Noor wrote on Twitter. "They had orchestrated the plot to trap Marshal Dostum and myself too, but they didn't succeed."

The flight of Noor and Dostum underlines the collapse not only of the central government in Kabul as the insurgents have swept forward but also of a generation of powerful regional leaders from the anti-Soviet Mujahideen who fought the Taliban.

Earlier in the week, Ismail Khan, one of the leaders of the original uprising that triggered the 1979 Soviet invasion, was captured by the Taliban in the western city of Herat and photographed surrounded by grinning insurgent fighters.

The importance of such leaders, sometimes described as "warlords", stemmed not from any official position in government but from their personal authority and regional power base and they frequently clashed with President Ashraf Ghani.

For years, they were accused of corruption and human rights abuses, with Dostum forced to spend a period in exile as recently as 2018 over allegations that he ordered a political opponent to be sexually assaulted.

Noor, considered one of the richest men in Afghanistan, faced repeated accusations of corruption, which he denied.

However as regular forces crumbled in the face of the Taliban following the withdrawal of U.S. forces, they returned to the front lines, in the hopes that their local power base would provide more effective resistance.

"Our path won't end here," Noor wrote.