President-elect Donald Trump says the US will quit the Trans-Pacific Partnership trade deal on his first day in the White House.
He made the announcement in a video message outlining what he intends to do first when he takes office in January.
The TPP trade deal was signed by 12 countries which together cover 40% of the world's economy.
Mr Trump also pledged to reduce "job-killing restrictions" on coal production and stop visa abuses.
But there was no mention of repealing Obamacare or building a wall on the southern border with Mexico, two actions he said during the campaign he would do as soon as he assumed power.
What is the TPP?
The massive trade deal was agreed in 2015 by nations including the US, Japan, Malaysia, Australia, New Zealand, Canada and Mexico, but has not yet been ratified by the individual countries.
Its aim was to deepen economic ties and boost growth, including by reducing tariffs.
There were also measures to enforce labour and environmental standards, copyrights, patents and other legal protections.
But its opponents say it was negotiated in secret and it favoured big corporations.
Why does Donald Trump dislike the TPP?
During the US presidential election campaign, Mr Trump gave broadbrush arguments against the pact, and used plenty of colourful language.
In June 2016 he described it as "another disaster done and pushed by special interests who want to rape our country, just a continuing rape of our country". In another speech he referred to the TPP as "the greatest danger yet".
But while there was plenty of talk about "taking back control" of the US economy, there were few specifics.
Announcing the plan to pull out of the TPP, he said that the US would "negotiate fair, bilateral trade deals that bring jobs and industry back onto American shores".
What else did Mr Trump say about his plans?
In the video message, Mr Trump said his governing agenda would be based on "putting America first" and that he and the new administration would "bring back our jobs".
Besides quitting the TPP, he committed to several other executive actions that he said he would take on day one.
He said he would cancel restrictions on US energy production. Last year, President Obama brought in the Clean Power Plan, an anti-climate change measure which aimed to reduce carbon emissions from the power sector by 32% by 2030 compared with 2005 levels.
The plan, already on hold due to legal challenges, would have restricted coal power plants and came up against strong opposition in areas where leaders said the plans would devastate local economies.
Mr Trump said: "I will cancel job-killing restrictions on the production of American energy, including shale energy and clean coal, creating many millions of high-paying jobs.
"That's what we want - that's what we've been waiting for."
Mr Trump, a real estate mogul himself, has been strongly opposed to business regulations throughout his campaign. He blamed them for stifling business. A month before the election, he said that if he won, 70% of regulations could be axed, but safety and environmental rules would stay.
Now he has pledged that for every new regulation brought into force, two old regulations will be eliminated.
In the video, Mr Trump also committed to:
- ordering a plan to combat cyber-attacks and other attacks
- investigating visa abuses that undercut American workers
- imposing a five-year ban on people leaving government to become lobbyists
What has been the reaction?
Political leaders and commentators in Asia in particular have reacted strongly. Japan's prime minister said the TPP would be "meaningless" without the involvement of the US and the economist Harumi Taguchi said China could move in to fill the "void" left by the deal's collapse.
China continues to push alternatives - the Regional Comprehensive Economic Partnership (RECP), which would include Japan, India and Australia, but not the US, and the Free Trade Area of the Asia Pacific (FTAAP).
China's foreign ministry said on Tuesday it would keep "pushing" to conclude talks on the RECP and warned against free trade agreements becoming "fragmented and politicised".
Malaysia's prime minister said it was President-elect Trump's right "to make the policy decisions he thinks right".
A spokesman for Canada's trade ministry said the government would continue to work on the TPP.
"We made a commitment to consult Canadians on the TPP and we will abide by that commitment," he told the BBC.
Analysis: Karishma Vaswani, Asia business correspondent
Asian leaders have had some time to prepare for this news - but that is not to say Mr Trump's decision will not sting.
The death of the TPP is a blow to many parts of emerging Asia.
Vietnam and Malaysia were set to gain the most from the deal. They already have access to the US markets for their products, but were hoping to see tariffs on some of their key exports vanish altogether.
Seven Asia-Pacific countries had signed up to the deal and for them, this may have lasting economic and political repercussions.
They could go ahead, as some have signalled, and continue with the deal on their own - but what would be the point without unfettered access to the US market?
What did Trump say about who would work with him?
The president-elect said in the video that "truly great and talented men and women, patriots are being brought in and many will soon be a part of our government".
He has spent the last week starting to put together his new team. Some key appointments have been made, but not without controversy.
Alabama Senator Jeff Sessions, who was turned down as a federal judge in 1986 due to racism complaints, will head the Justice Department.
And the news that Steve Bannon, former editor-in-chief of the conservative Breitbart website, was the new White House strategist was welcomed by former Ku Klux Klan leader David Duke.
Meanwhile, one of Mr Trump's immigration advisers, Kris Kobach, was photographed meeting the president-elect while holding a document that contained some hardline proposals.
Among them was the reintroduction of registration for people arriving from mostly Muslim countries, which was brought in after the 11 September attacks but later dropped.