Arms-control groups welcomed the United States' decision to stop making and buying anti-personnel landmines, describing it as a small yet significant step forward.
The United States announced its decision on Friday at a conference in Maputo, Mozambique, to review the Mine Ban Treaty, also known as the Ottawa Convention. Human Rights Watch said Washington was moving in the right direction but that it had not gone far enough.
"It makes little sense to acknowledge that the weapons must be banned due to the humanitarian harm they cause, and yet to insist on being able to use them," said Steve Goose, of HRW.
Though the US has not been known to use antipersonnel landmines in combat for more than two decades, the "vague position" may do little to spur other major powers like China and Russia to sign the treaty, said Elizabeth MacNairn, executive director of Handicap International, an aid organisation that works with landmine victims.
"By not setting a firm date to complete this task, the US runs the risk of allowing its landmine policy review to drift beyond President Obama's term in office as president," MacNairn said.
Besides the United States, 35 countries have not acceded to the Mine Ban Treaty. They include Russia, China, India, Pakistan, Myanmar and North and South Korea. The administration of Barack Obama's predecessor George W. Bush in 2004 said it would not sign the ban.
Obama's decision comes just months after US Army General Martin Dempsey, chairman of the Joint Chiefs of Staff, told a congressional panel that he believed landmines were "an important tool in the arsenal of the armed forces".
Democratic Senator Patrick Leahy, who has pushed for a ban, called the White House's action "incremental, but significant". He added: "An obvious next step is for the Pentagon to destroy its remaining stockpile of mines, which do not belong in the arsenal of civilised nations."
Douglas Griffiths, the US ambassador to Mozambique, announced the decision. It was later confirmed by Washington.
"The United States took the step of declaring it will not produce or otherwise acquire any antipersonnel landmines in the future, including to replace existing stockpiles as they expire," the White House said in a statement.
Congressman Randy Forbes warned the decision would threaten security on the Korean peninsula, and congressman Buck McKeon, chairman of the House of Representatives Armed Services Committee, said it was "bad for the security of our men and women in uniform".
The United States stopped using long-life anti-personnel mines in 2011 and agreed to destroy its stockpile of 1.3 million of them. It maintains a supply of so-called smart landmines that can deactivate or self-destruct.
Rear Admiral John Kirby, the Pentagon press secretary, said the US had just over three million antipersonnel mines stockpiled.
Kirby said the Pentagon expected that about 10 years from now mines in the current stockpile would start losing their effectiveness "and 10 years after that they'll be completely unusable".
The US has not produced landmines since the late 1990s.
Landmines kill 15,000 to 20,000 people every year, according to a 2008 United Nations report. The Mine Ban Treaty became international law in 1999.
Additional reporting by The Washington Post, Associated Press