US President Donald Trump has cancelled a prohibition on the use of anti-personnel landmines outside of the Korean peninsula, saying the previous policy could put American troops at a "severe disadvantage".

Key points: The Trump Administration has cited "great power competition" in overturning the ban

The Trump Administration has cited "great power competition" in overturning the ban Around 160 countries around the world have banned landmines

Around 160 countries around the world have banned landmines Thousands of people die from landmines every year, mostly civilians

The policy change drew swift condemnation from groups that have advocated for a global ban on landmines, which have been widely condemned for their history of killing and maiming children and other civilians long after wars are over.

Under a policy introduced in 2014, then-president Barack Obama had prohibited the military from using any landmines anywhere in the world except in defence of South Korea.

In a statement, the White House said the Pentagon had determined the restrictions could put troops at a disadvantage, stating they should be allowed to use the explosive devices in "exceptional circumstances".

The Trump Administration says the move is intended to keep the US military the "greatest fighting force in the world." ( AP: Susan Walsh )

"This policy will authorise Combatant Commanders, in exceptional circumstances, to employ advanced, non-persistent landmines specifically designed to reduce unintended harm to civilians and partner forces," the White House said.

White House press secretary Stephanie Grisham said that the move was "another in a series of actions taken by the Trump Administration to give our military the flexibility and capability it needs to win" and "forever remain the greatest fighting force in the world".

Vic Mercado, who is performing the duties of assistant secretary of defence for strategy, plans and capabilities at the Pentagon, said the focus of the policy was on "great power competition" — referring to China and Russia.

Asked whether he could foresee landmines being used by US forces in war zones like Afghanistan or Syria, he said, "I don't see that right now".

Mr Mercado said the US will "continue to lead in international humanitarian de-mining efforts that locate and remove landmines and explosive remnants of war that pose persistent threats to civilians living in current and former conflict areas around the world".

Democratic senator Patrick Leahy criticised the move, calling it "as perplexing as it is disappointing, and reflexive, and unwise".

"Most of the world's countries have embraced the ban on antipersonnel landmines for more than two decades, while the Trump administration has done a complete about-face in deciding to cling to these weapons in perpetuity," said Human Rights Watch's arms division director, Steve Goose, in a statement.

"Using landmines, which have claimed so many lives and limbs, is not justified by any country or group under any circumstances."

The United States is not a signatory to the 1997 Mine Ban Treaty, which took effect in 1999 and broadly prohibits the development, use and acquisition of anti-personnel land mines.

Washington had abided by many provisions of the treaty, which had been endorsed by more than 160 countries.

According to Landmine Monitor, an expert watchdog, at least 7,239 people were killed or injured by antipersonnel and antivehicle landmines in 2017.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 4 seconds 1 m 4 s In April, Donald Trump announced he would "never ratify the UN arms trade treaty".

Its database recorded some 120,000 casualties worldwide between 1999 and 2017. Civilians generally account for more than 70 per cent of those killed.

"There is a reason why the use of antipersonnel landmines is illegal: they can't distinguish between fighters and ordinary people," said Adotei Akwei of Amnesty International USA.

"This decision is consistent with an administration that has proven itself indifferent to human lives and suffering by withdrawing from the global Arms Trade Treaty and more recently by easing oversight of US arms exports."

ABC/wires