International war crimes judges ruled Thursday that a probe into wartime abuses in Afghanistan must go ahead, including looking into possible atrocities committed by US forces, as they overturned a previous court ruling.

Pre-trial judges at the Hague-based International Criminal Court last year rejected a demand by its chief prosecutor to open a full-blown probe into crimes committed in the war-torn nation -- an investigation also bitterly opposed by Washington.

Prosecutors appealed the move, saying that the judges made an error when they slapped down Fatou Bensouda's request by saying although it met all the right criteria and a reasonable basis, it was "not in the interest of justice."

The appeals judges agreed with the prosecution.

"The prosecutor is authorised to commence an investigation into alleged crimes committed on the territory of Afghanistan since May 1, 2003," ICC judge Piotr Hofmanski said.

"It is for the prosecutor to determine whether there is a reasonable basis to initiate an investigation," under the court's statutes, Judge Hofmanski said.

Pre-trial judges are only called upon to see if there is a reasonable basis to proceed with an investigation not to "review the Prosecutor's analysis," he said.  

In 2006, the ICC's prosecutors opened a preliminary probe into possible war crimes and crimes against humanity in the central Asian nation since 2003.

In 2017 Bensouda asked judges to allow a full-blown inquiry, not only into Taliban and Afghan government personnel but also international forces, US troops and members of the Central Intelligence Agency.

But pre-trial judges then said it "would not serve the interests of justice" and that the court should focus on cases with a better chance of success.

- 'Much-needed signal' -
 

Human rights groups on Thursday hailed the decision to uphold the prosecutions' appeal.

"The decision also sends a much-needed signal to current and would-be perpetrators of atrocities that justice may one day catch up to them," Human Rights Watch's Param-Preet Singh said.

Bensouda's move however have unleashed a backlash from Washington, which in April last year revoked the Gambian-born chief prosecutor's visa as part of broader restrictions on ICC staff probing American or allied personnel.

Former national security advisor John Bolton warned in 2018 that the US would arrest ICC judges if the court pursued an Afghan probe.

The US has never joined the ICC and does not recognise its authority over American citizens, saying it poses a threat to national sovereignty.

Washington argues that it has its own procedures in place to deal with US troops who engage in misconduct.

Afghanistan also opposes the inquiry, saying the country itself had "responsibility to bring justice for our nation and for our people".

The ICC's ruling comes days after Taliban militants killed at least 20 Afghan soldiers and policemen in a string of overnight attacks, throwing the country's nascent peace process into grave doubt.

Under the terms of a recent US-Taliban agreement, foreign forces will quit Afghanistan within 14 months, subject to Taliban security guarantees and a pledge by the insurgents to hold talks with Kabul.

A US-led force invaded Afghanistan in 2001 following the 9/11 terror attacks in the US, targeting Al-Qaeda in the sanctuaries provided by the Taliban government.

Fighting has continued ever since -- last year more than 3,400 civilians were killed and almost 7,000 injured, according to data provided by UN agencies.