President Donald Trump has warned that the United States would "no longer turn a blind eye" to what he describes as unfair trade practices.
Trump became the first sitting president in 18 years to address the World Economic forum at Davos, closing the summit with a speech in which he declared the US was "open for business".
He also said he would always put the US first when it came to trade, but "that does not mean America alone".
"Now is the best time to bring your money, your jobs, your businesses to America," Trump said, singling out tax cuts and curbs to regulation as boosting the investment climate.
"The world is witnessing the resurgence of a strong and prosperous America."
Trump said he would always promote "America First" but added: "America First does not mean America alone. When the United States grows so does the world,"
Trump also accused unidentified countries of unfair practices, including stealing intellectual property and providing state aid to industry.
And he warned: "We will enforce our trade laws and restore integrity to the trading system. Only by insisting on fair and reciprocal trade can we create a system that works not just for the United States but for all nations.
"The United States will no longer turn a blind eye to unfair trade practices," he said.
"We cannot have free and open trade if some countries exploit the system at the expense of others. We support free trade but it needs to be fair and it needs to be reciprocal."
While he has a record of opposing multilateral trade agreements involving many countries, Trump said the US would consider "mutually beneficial" bilateral trade agreements with other individual states.
That could include those signed up to a Trans-Pacific trade agreement from which he has withdrawn, he said, adding that he would also consider negotiating with them collectively if that was in the US interest.
Earlier in the week US Treasury Secretary Steven Mnuchin said the US benefited from a lower dollar, which would make its exports cheaper.
Mnuchin's remarks drew sharp rebukes from the European Central Bank.
But on Thursday, Trump said he ultimately wants the dollar to be strong, lifting the greenback briefly.
