Former Speaker of the US House of Representatives Newt Gingrich has slammed President Joe Biden for withdrawing troops from Afghanistan, saying the decision would leave South Korea and other allies wondering whether they can trust the United States.

Gingrich made the comments in a contribution to Fox News on Wednesday, portraying the turmoil in Afghanistan in the wake of the US' troop withdrawal decision as a "clearly massive failure of leadership."

"See how quickly Biden turns his back on allies when he's trying to save face? Can you also see how dangerous this is for America?" Gingrich wrote. "With the world watching the Biden decision to chaotically cut and run on an ally, why should Taiwan, the Europeans, South Korea, or any other ally trust and rely on President Biden?"

His remarks came as the US' chaotic exit from the war-torn country cast doubts over Biden's commitments to shoring up the US' global leadership role and reinforcing alliances, which his administration has called the "greatest strategic asset."

Observers have also raised concerns about the credibility of the US' security commitments to allies, as America's pullout from Afghanistan signaled Washington's apparent tendency to engage only where key interests are at stake.

Gingrich also took a swipe at Biden's focus on human rights at the core of his foreign policy.

"How could Biden say, 'I have been clear that human rights must be the center of our foreign policy, not the periphery,' as the Taliban begins to oppress every woman and girl in the country and institute a policy of seizing women and girls to force them to marry Taliban fighters?" he said.

Brushing aside criticism at home and abroad, Biden has shifted the blame to the Afghan military and Kabul political leaders for a lack of willingness to fight for their own nation and make their own future, while American troops have borne the brunt of the protracted war. (Yonhap)