A months-long drive by the US to engage with the Taliban has ostensibly been aimed at convincing them to talk to Kabul, but the Taliban see President Ashraf Ghani and his government as US-backed puppets.

"Ultimately, we need to get to a Taliban-Afghanistan discussion," General Joseph Votel, the head of US Central Command, told US lawmakers.

"Only they will be able to resolve the key issues involved in the dispute."

The talks, led by US special envoy Zalmay Khalilzad, come as President Donald Trump seeks to pull US troops from Afghanistan.

"I would characterize where we are in the process as very, very early in the process," Votel said.

"Ambassador Khalilzad is attempting to create a framework by which we can move forward with discussions. That would be certainly involving the government of Afghanistan."

Ghani said Tuesday on Twitter that he had spoken to US Secretary of State Mike Pompeo, who "underscored the central importance of ensuring the centrality of the Afghan government in the peace process."

The Taliban meanwhile are meeting with envoys, many with competing interests in Afghanistan.

On Tuesday in Moscow, they met Afghan politicians from outside the government and demanded a new constitution for Afghanistan while promising an "inclusive Islamic system."

While no representatives from the Kabul government were invited, some of Ghani's chief rivals -- including former president Hamid Karzai -- were there.