US president Donald Trump told the National Rifle Association he was pulling the United States out of an international arms treaty signed in 2013.
Mr Trump said he intends to revoke the status of the United States as a signatory to the Arms Trade Treaty, which was never ratified by the US Senate.
“We’re taking our signature back,” Mr Trump said to thousands of cheering attendees at a convention on Friday.
In reversing the US position on the pact, he wrote on Twitter, “We will never allow foreign bureaucrats to trample on your Second Amendment freedoms.”
The NRA has long opposed the treaty, which regulates the $70 billion business in conventional arms and seeks to keep weapons out of the hands of human rights abusers. The lobbying group argues it would undermine domestic gun rights, a view the Obama administration rejected.
The agreement covers weapons exports, ranging from small firearms to tanks, but not domestic sales.
Mr Trump said the United Nations would soon receive formal notice of the withdrawal.
UN spokesman Stephane Dujarric called the treaty “a landmark achievement in the efforts to ensure responsibility in international arms transfers”. UN officials said they were unaware Mr Trump had been planning to revoke the US signature.
The NRA spent $30.3 million in support of Mr Trump’s 2016 presidential campaign, according to the Center for Responsive Politics, a group that tracks campaign spending.
The 193-nation UN General Assembly overwhelmingly approved the pact in April 2013 and the United States, the world’s number one arms exporter, voted in favor of it despite fierce opposition from the NRA.
Dropping out of the treaty is part of a broader Trump administration overhaul of arms export policies to bolster a domestic industry that already dominates global weapons trade.
International human rights groups criticised Mr Trump’s decision.
“The United States will now lock arms with Iran, North Korea and Syria as non-signatories to this historic treaty whose sole purpose is to protect innocent people from deadly weapons,” said Oxfam America president Abby Maxman.
So far 101 countries have formally joined onto the treaty. Another 29, including the United States, signed it, but have not yet formally joined.
Rachel Stohl, director of the conventional defense program at the Stimson Center think-tank in Washington, said US firearms makers could now benefit, including Smith & Wesson owner American Outdoor Brands Corp, Sturm Ruger and Vista Outdoor, as well as the private equity firm Cerberus Capital Management, which owns Bushmaster, a brand of AR-15 assault rifle.
Mr Trump was joined on his trip to the NRA's meeting in Indianapolis by White House national security adviser John Bolton, an advocate of withdrawing the United States from international treaties out of concern they might undermine US authority.
Friday’s speech marked the third consecutive year Mr Trump has spoken to the annual meeting of the NRA. Since his election, he has been a vocal proponent of gun rights, a position that plays well with his political base.