Donald Trump has said the United Nations is just a club for people to "have a good time", days after the world body voted to condemn Israeli settlements in the West Bank and east Jerusalem.
The US president-elect said on Twitter that the UN had "such great potential", but had become "just a club for people to get together, talk and have a good time. So sad!".
The United Nations has such great potential but right now it is just a club for people to get together, talk and have a good time. So sad!— Donald J. Trump (@realDonaldTrump) December 26, 2016
On Friday, billionaire property mogul Mr Trump warned: "As to the UN, things will be different after January 20th" - referring to the day he takes office.
The decision by the Obama administration to abstain from Friday's UN vote brushed aside Mr Trump's demands that the US exercise its Security Council veto and provided a climax to years of icy relations with Israel's leadership.
Mr Trump said last December that he wanted to be "very neutral" on Israel-Palestinian issues. But his tone became decidedly more pro-Israel as the presidential campaign progressed. He has spoken disparagingly of Palestinians, saying they have been "taken over" by or are condoning militant groups.
His tweet on Monday about the UN ignores much of the work that goes on in the 193-member organisation.
This year the Security Council has approved more than 70 legally binding resolutions, including new sanctions on North Korea and measures tackling conflicts and authorising the UN's far-flung peacekeeping operations around the world.
The General Assembly has also approved dozens of resolutions on issues like the role of diamonds in fuelling conflicts, condemned human rights abuses in Iran and North Korea and authorised an investigation of alleged war crimes in Syria.
Mr Trump's criticism of the UN is by no means unique. While the organisation does engage in large-scale humanitarian and peacekeeping efforts, its massive bureaucracy has long been a source of controversy.
It has been accused by some Western governments of being inefficient and frivolous, while developing nations have said it is overly influenced by wealthier nations.
Mr Trump tweeted later on Monday: "The world was gloomy before I won - there was no hope. Now the market is up nearly 10 percent and Christmas spending is over a trillion dollars!".
Markets are up since Mr Trump won the presidential election, although not quite by that much. The Standard & Poor's 500 is up about 6% since election day, while the Dow has risen more than 8%.
As for holiday spending, auditing and accounting firm Deloitte projected in September that total 2016 holiday sales were expected to exceed one trillion dollars, representing a 3.6-4% increase in holiday sales from November through January.
The president-elect is spending the holidays at his Mar-a-Lago resort in Florida.