Kabul, Dec 16 (AFP) The US military can slash its troop presence in Afghanistan and still pack a "lethal punch," an influential American lawmaker and close confidant to President Donald Trump said Monday.

Republican Senator Lindsey Graham also said it would be "insane" for the US to trust the Taliban to keep Al-Qaeda and other jihadists in check, attacking a cornerstone of a prospective deal between Washington and the Taliban. Graham's remarks came a day after US media reported that the Trump administration could announce plans as early this week to withdraw around 4,000 troops from Afghanistan.

The drawdown would mean about 8,600 US troops remained in Afghanistan, down from the current total of between 12-13,000.

Graham suggested the official announcement might not be as imminent as was suggested in the American press.

"If President Trump decides in the next few weeks to reduce our forces below the 12,000 we have, I could support that," Graham told reporters in Kabul. "With 8,600 American forces aligned in the right configuration, we would have a very lethal punch".

Addressing the on-again, off-again negotiations between the US and the Taliban that have been taking place in Doha this year, Graham took issue with a central component of an eventual deal, which centres on the US withdrawing forces in return for a Taliban promise to fight Al-Qaeda and the Islamic State group.

"The Taliban may not be trusted to be a reliable counterterrorism force," Graham said.

"The idea that any agreement would count on the Taliban to police, be the counterterrorism force to the American homeland, is a nonstarter."

Graham is thought to have been key in persuading Trump in September to drop the deal with the Taliban, even though the US and the insurgents had all but signed off on it.

In order to get talks back on track, the Taliban in recent weeks have reduced violence in Kabul.

But Graham suggested the insurgents were still not to be trusted, referencing a deadly attack at Bagram air base outside of Kabul last week.

"To the brilliant masterminds who planned the Bagram attack, you've probably done more to set back the process than anything I could think of," the senator said. "It would be insane for America to rely on the Taliban to ensure that al-Qaeda and ISIS-K doesn't come back," he said.

Graham also briefly visited Pakistan, where he met with Prime Minister Imran Khan. Graham, who has made various public assessments about the extent of Islamabad's support of the Taliban, said Trump's relationship with Khan was strong and possible trade deals could be coming.

"I told President Trump that the one thing that no one's really ever done in this long war is set out in Pakistan and say, OK, let's talk about a free trade agreement. ... But here are the things that we want you to do on the security side," Graham said. (AFP)

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