Afghan authorities have resumed a controversial release of Taliban inmates, an insurgent spokesman said Tuesday, marking an important step toward breaking an impasse that has delayed the start of peace talks for months.

"Our prisoners have been released and we see this as a positive step that paves the ground for the start of intra-Afghan talks," Taliban spokesman Suhail Shaheen told AFP.

Negotiations were initially supposed to begin in March but were repeatedly pushed back as the Taliban and the Afghan government squabbled over the prisoner exchange, which included hundreds of battle-hardened insurgents.

Another Taliban official from the group's prison commission said 200 prisoners had been released by Kabul since Monday.

He said in return for their prisoners, the militants had released four Afghan commandos who had been held captive, adding that two more would be freed on Wednesday.

A senior Afghan government official told AFP that "dozens" of Taliban prisoners had been released on Monday.

"The remaining prisoners will be released within a couple of days," he said.

Under the terms of a US-Taliban deal in February, Kabul was supposed to free 5,000 militants and the Taliban were meant to free 1,000 Afghan troops.