Abolishing militant hideouts in Pakistan is critical to establishing peace in neighbouring Afghanistan, Afghan President Ashraf Ghani said on Thursday before meeting United States (US) President Donald Trump on the sidelines of the United Nations General Assembly (UNGA).

Neither Trump nor Ghani mentioned Pakistan when they appeared publicly together after their discussion. But Ghani said Pakistan's role is a key part of the Trump plan announced last month to end America's longest war and eliminate a rising extremist threat in Afghanistan.

“Reduction of safe havens is absolutely necessary,” Ghani told National Public Radio in an interview broadcast on Thursday.

The Trump administration in August infuriated Pakistan by accusing Islamabad of providing extremists haven.

The US also has threatened to withhold military aid despite Pakistan's repeat assertions that it has acted against Taliban insurgents and members of the Haqqani network.

“I hope that this time, Pakistan will get the message loud and clear that business as usual cannot continue. It's not in their interest. It's not in anyone's interest,” Ghani said.

“Pakistan has never had this type of dialogue with the US and I hope that wisdom and shared national interests will prevail.”

After meeting Ghani, Trump praised efforts to drive the Taliban and militant groups out of Afghanistan.

He said joint Afghan-US forces have made headway against Taliban, “hitting them hard and hitting them effectively.”

Senior officials have said Trump's plan for Afghanistan involves sending up to 3,900 additional US troops on top of the roughly 8,400 Americans now in the country.

Ghani stressed that Afghan forces are leading the fight. He said he isn't seeking “a blank check” of unlimited American help.

Ghani said earlier in the week the Trump administration's four-year objective is to bring 80 per cent of the country back under the government's control. The Taliban currently hold sway in nearly half of the nation.