KABUL (BLOOMBERG) - US Secretary of Defence Lloyd Austin paid an unannounced visit to Afghanistan on Sunday (March 21), the Associated Press said, citing local media reports.

The stop comes as President Joe Biden is under pressure to decide whether to abide by an Afghanistan peace deal reached in his predecessor Donald Trump's final year aimed at bringing home the roughly 2,500 troops remaining in the country by May 1.

It's a deadline that Mr Biden has said "could happen" but would be "tough" to meet.

"I'm in the process of making that decision now as to when they'll leave," Mr Biden told ABC News.

"That was not a very solidly negotiated deal that the president - the former president - worked out."

Mr Austin pledged in February a "thoughtful and deliberate" review of US strategy in Afghanistan, saying there would be "no surprises" for the Afghan government or allies with troops in the country.

A deal reached last year provided the opportunity to wind down the US role, but on condition that violence declined, the Taleban pledged to bar terrorist groups like Al-Qaeda and Islamic State in Iraq and Syria (ISIS) from operating in the country, and the government and the Taleban entered productive peace talks.

That process dragged out, but the Trump administration stuck with it. The Taleban, on the cusp of seeing foreign forces depart, largely held off on attacking Americans.

Despite last year's accord, the security situation in Afghanistan is worsening.

Violence has climbed since the peace talks started in September last year, including targeted killings of journalists, civil society members and politicians.

In 2020, 8,820 Afghan civilians were killed or wounded, according to the United Nations.

Previous peace efforts between the Taleban insurgents and President Ashraf Ghani's government in Doha, Qatar, have made little headway, with the two sides taking months even to agree on the basic outline of the talks.

US Secretary of State Antony Blinken said in a letter to Mr Ghani that even with continued US financial aid, "the Taleban could make rapid territorial gains" if the US withdraws and there's no agreement reached between the Afghan government and the Taleban.

He added bluntly: "I am making this clear to you so that you understand the urgency of my tone regarding the collective work outlined in this letter."

Mr Austin's reported stop in Afghanistan comes after a trip that took him to Japan, South Korea and India.