Afghanistan's President Ashraf Ghani urged the new US administration Friday to step up pressure on the Taliban and not rush to withdraw more troops.

Ghani said the Taliban have failed to live up to conditions agreed in their February 2020 deal with the United States to reduce attacks in Afghanistan and sever longstanding ties to Al-Qaeda.

"The United States and NATO must take a very strong stand on the conditions-based approach," Ghani said in an online address to the Aspen Security Forum.

"They signed an agreement; that agreement now needs to be implemented."

Even though Taliban and Afghan government negotiators opened peace talks in Doha last year, violence in Afghanistan has soared. 

Ghani said the Taliban must admit to attacking government forces and conducting a string of assassinations of public figures. 

The Taliban exploited former president Donald Trump's rush to pull US forces from Afghanistan to continue attacking government forces, Ghani suggested.

After the US-Taliban deal last year, US officials assured Kabul "there will be a ceasefire or a very substantial reduction of violence," Ghani said.

"Instead, violence has peaked," he said. 

And rather than pursuing peace talks in good faith, "the Taliban are finding one excuse after another not to meet."

Ghani said he spoke with new US Secretary of State Antony Blinken on Thursday and was assured that President Joe Biden's administration would review matters by sending a new team to Afghanistan, and would consult more closely with Kabul.

"We couldn't be more pleased with the early focused, systematic attention and a dialog between two partners that have mutually sacrificed and have a mutual interest," he said.

The Taliban believe they defeated the US and that NATO forces in Afghanistan are "on the run", Ghani said.

"Now, robust diplomacy and a stand on conditions-based approaches will enable us all hopefully to resume meaningful discussion," he added.

The United States has about 2,500 troops in Afghanistan, down from close to 13,000 a year ago.

In the Trump administration's withdrawal deal with the Taliban, the US was supposed to pull all troops out by May 2021 in return for security pledges from the insurgents.

Ghani said US forces need to remain, without specifying how many. He said he expected Biden to make "the right decision."

"NATO without US enablers cannot continue its mission," he said.

If the "Taliban realise that they can prevail through violence, they will not let go," he added. 

"A combination of presence, plus diplomacy, bringing US tools of power in a concentrated manner.... would be extremely crucial to our success."