The Afghan Taliban said Wednesday they had not been officially contacted by Kabul about the resumption of direct talks aimed at ending their conflict.

The comment came a day after the latest round of dialogue in the Afghan capital between officials from Afghanistan, the United States, China and Pakistan.

The representatives of the four states called on the militants to return to the negotiating table and said they expect the process to begin by the first week of March.

"We are not aware of this, I cannot say anything regarding talks in Islamabad," said the Islamist group's spokesman Zabihullah Mujahid in a phone conversation.

"We have not received anything officially in this regard, we only heard it from media."

A first round of direct talks with the Taliban took place in the Pakistani resort town of Murree last July, but came to a standstill after the Kabul government leaked news of the death of Taliban leader Mullah Omar two years before.

The announcement, and the appointment of his successor Mullah Akhtar Mansour, accentuated divisions among the militants, with many holding Mansour responsible for lying to them about Omar's death.

A splinter group formed under Mullah Rasool and challenged Mansour's leadership.

But the disunity has not dented the Taliban's fighting ability.

The insurgents are waging an unprecedented winter campaign of violence across Afghanistan, underscoring a worsening security situation more than 14 years after their government in Kabul was toppled by a US-led invasion.

In January, during a seminar organised by the Pugwash peace movement in Qatar, Taliban representatives called for their cadres to be removed from US and UN blacklists which have frozen their assets and restricted their freedom of movement.

In addition, they have said talks cannot take place until the withdrawal of some 13,000 NATO troops still deployed in Afghanistan.

"We have expressed our position clearly in the Pugwash conference," Mujahid told AFP.