U.S. President Donald Trump | Jim Watson/AFP via Getty Images Trump: ‘We’re a developing nation, too’ US president says ‘we’re going to do something very dramatic’ with the WTO.

U.S. President Donald Trump took another shot at the World Trade Organization on Wednesday, saying it had been "very unfair to the U.S. for many, many years."

Speaking at the World Economic Forum in Davos, which he described as a "tremendous success," Trump said he takes exception to the WTO's practice of favoring developing nations over developed ones when it comes to trade terms, insisting that "as far as I'm concerned we're a developing nation, too."

He described WTO Director-General Roberto Azevêdo as "highly respected" and said talks between the two were ongoing. "Roberto and I have a tremendous relationship ... and we're going to do something very dramatic," Trump said.

Also speaking at the WEF, Azevêdo said "the system has not been functioning properly in many areas," and said he would soon "discuss with President Trump what needs to change."

Asked about climate activist Greta Thunberg and her criticism of his climate politics, Trump said she "has to start working on those other countries."

"Our environmental numbers are very very good ... our numbers on air are tremendous," he said. "We're clean and beautiful and everything's good, but Greta ought to focus on [other regions]."