Red, white and blue balloons rained down over crystal chandeliers in the soaring atrium of the Trump International Hotel at midnight in “a new inaugural tradition,” its social media account promised.

But while President Donald Trump's hotel in Washington did serve as a hub of Friday's inaugural activities, it also stands as ground zero for what top Democrats and some ethics advisers see as his unique web of conflicts of interest.

Trump's lease with the federal government to develop and operate a hotel inside the historic Old Post Office building expressly prohibits any elected official from benefiting from the property, yet Trump has not divested from his company or this particular project.

The government's General Services Administration previously said it would refrain from commenting on the apparent contract violation until Trump took office, which he did at noon on Friday. The agency did not respond to requests for comment.

“I think it's a simple matter of amending the lease,” said Patrick Keogh, a real estate investor in Austin, Texas, who has developed projects for the GSA and other federal agencies. He said Ivanka Trump, the President's daughter and chief negotiator on the hotel, should ask the GSA to exempt her father from that provision of the contract. The GSA should make the process public and transparent, Keogh said.

Others say Trump must relinquish ownership of the hotel. More broadly, they argue, Trump should sell off his company and put the cash into a blind trust as previous presidents have done. He is not legally required to do so, but it has become common for presidents to separate themselves from their personal finances to avoid any possible conflicts with national policy.

The liberal-funded watchdog group Citizens for Responsibility and Ethics in Washington complained to the GSA that it should terminate its deal or take legal action because the President had violated the conditions of the lease. The American Civil Liberties Union said it had filed a Freedom of Information Act request for documents about Trump's conflicts of interest, including any recent memos, emails and other private communications on the issue with his transition team.

The Washington hotel also attracted protesters on Friday and Saturday. People participating in the women's march on Saturday booed in unison as they walked by, and many left their protest signs in front of the building.

Trump handed control of his international real estate development, property management and licensing company to his two adult sons. To help ease the appearance of conflicts of interest, the company said it would not enter into any new international deals, promised to hire a compliance officer and ethics adviser to vet domestic deals, donate foreign profit from its hotels and refrain from doing anything that could be perceived as exploiting the office of the presidency.

“The Trump Organisation has directed that no communications of the organisation, including social media accounts, will reference or otherwise be tied to President-elect Trump's role as president of the United States or the office of the presidency,” a company attorney wrote in a briefing released earlier this month.

Trump has voluntarily taken these measures, since few conflict laws apply to the President or Vice President. That means people will have to trust that the President and his company are following through.

“We are waiting for you, Mr. President! Thank you!” Trump's Washington hotel wrote on its Twitter account shortly before the President was scheduled to roll past the Pennsylvania Avenue property as part of the inaugural parade. Indeed, Trump hopped out of his motorcade to walk and wave in front of the hotel.

The tweet would appear to violate the company's no-reference-to-the-President policy.

Trump Organisation representatives did not respond to requests for comment.

Patricia Tang, the Washington hotel's director of sales and marketing – who said she was responsible for social media – did not directly answer questions about the possible violation. But she said, “We have nothing to do with the administration. We have nothing to do with the presidency. We just want to be the best possible luxury hotel that we can be.”

The new White House raised eyebrows on its first day by posting on its official website a biography of the first lady Melania Trump that included an explicit reference to her jewellery collection, which it noted was sold on the home-shopping channel QVC. By Saturday, that line had been edited and simplified to say that she had “launched her own jewellery collection.”

A spokeswoman for the First Lady said the website was updated out of “an abundance of caution” and that the jewellery line is no longer available in any case.

In pictures: Protests, pomp and Donald Trump Show all 30 1 /30 In pictures: Protests, pomp and Donald Trump In pictures: Protests, pomp and Donald Trump President-elect Donald Trump acknowledges guests as he arrives on the platform at the US Capitol in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Donald Trump is sworn in as the 45th president of the United States by Chief Justice John Roberts as Melania Trump looks on during the 58th Presidential Inauguration at the U.S. Capitol in Washington AP In pictures: Protests, pomp and Donald Trump President Donald Trump shakes hands with Justice John Roberts after taking the oath at inauguration ceremonies swearing in Trump as the 45th president of the United States Reuters In pictures: Protests, pomp and Donald Trump President Donald Trump raises his fists after his inauguration on the West Front of the U.S. Capitol Getty In pictures: Protests, pomp and Donald Trump U.S. President-elect Donald Trump greets outgoing President Barack Obama before Trump is inaugurated during ceremonies on the Capitol in Washington Reuters In pictures: Protests, pomp and Donald Trump resident-elect Donald Trump arrives on the platform of the US Capitol in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Attendees partake in the inauguration ceremonies to swear in Donald Trump as the 45th president of the United States at the U.S. Capitol in Washington DC Reuters In pictures: Protests, pomp and Donald Trump US President Donald Trump delivers his inaugural address during ceremonies at the US Capitol in Washington DC Getty In pictures: Protests, pomp and Donald Trump U.S. President Donald Trump waves with wife Melania during the Inaugural Parade in Washington DC Reuters In pictures: Protests, pomp and Donald Trump Protesters registered their rage against the new president Friday in a chaotic confrontation with police who used pepper spray and stun grenades in a melee just blocks from Donald Trump's inaugural parade route. Scores were arrested for trashing property and attacking officers AP In pictures: Protests, pomp and Donald Trump Demonstrators protest against US President Donald Trump in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump A woman holds a sign before the start of the Presidential Inauguration of Donald Trump at Freedom Plaza in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Anti-Trump protesters prepare banners for a protest against the inauguration of US President-elect Donald Trump, in Berlin REUTERS In pictures: Protests, pomp and Donald Trump Demonstrators shout slogans against US President-elect Donald Trump in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Demonstrators march, block foot traffic and clash with U.S. Capitol Police at the entry checkpoints for the Inauguration of Donald Trump Alamy Live News In pictures: Protests, pomp and Donald Trump Demonstrators display a banner as people arrive for US President-elect Donald Trump's inauguration in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump A man displays a placard as people lineup to get into the National Mall for the inauguration of US President-elect Donald Trump in Washington DC Getty Images In pictures: Protests, pomp and Donald Trump Protesters demonstrating against U.S. President Donald Trump raise their hands as they are surrounded by police on the sidelines of the inauguration in Washington DC Reuters In pictures: Protests, pomp and Donald Trump A demonstrator wearing a mask depicting Donald Trump protests outside the US Embassy in London Getty Images In pictures: Protests, pomp and Donald Trump Demonstrators hold placards as they protest outside the US Embassy in London Getty Images In pictures: Protests, pomp and Donald Trump Former US President George W. Bush and First Lady Laura Bush arrive for the Presidential Inauguration at the US Capitol Rex In pictures: Protests, pomp and Donald Trump Michelle Obama and Dr. Jill Biden share an umbrella as President Donald Trump delivers his inaugural address at the inauguration in Washington DC Rex In pictures: Protests, pomp and Donald Trump Former Democratic presidential nominee Hillary Clinton and former President Bill Clinton arrive on the West Front of the U.S. Capitol in Washington Reuters In pictures: Protests, pomp and Donald Trump U.S. Vice President Mike Pence takes the oath of office on the West Front of the U.S. Capitol in Washington, DC Getty Images In pictures: Protests, pomp and Donald Trump Advisors to President-elect Donald Trump, Kellyanne Conway and Steve Bannon depart from services at St. John's Church during the Presidential Inauguration in Washington Reuters In pictures: Protests, pomp and Donald Trump Protesters demonstrating against U.S. President Donald Trump take cover as they are hit by pepper spray by police on the sidelines of the inauguration in Washington DC Reuters In pictures: Protests, pomp and Donald Trump An activist demonstrating against U.S. President Donald Trump is helped after being hit by pepper spray on the sidelines of the inauguration in Washington DC Reuters In pictures: Protests, pomp and Donald Trump A police officer tries to tackle a protester demonstrating against U.S. President Donald Trump Reuters/Adrees Latif In pictures: Protests, pomp and Donald Trump Police arrest and detain a protester in the street in Washington DC Rex In pictures: Protests, pomp and Donald Trump A police officer falls to the ground as another shoots pepper spray at protesters demonstrating against U.S. President Donald Trump on the sidelines of the inauguration in Washington DC Reuters

There have also been questions about what the Trump Organisation means by no “new” foreign deals.

Earlier this week, the company confirmed it wanted to expand at one of its Scottish resorts, including plans to add a golf course. A spokeswoman for the resort said the expansion is just another “phase” of a project outlined in a planning document approved by the local government years ago, and so did not break any Trump promise.

But Richard Painter, chief ethics lawyer under former President George W. Bush, said every phase of a real estate project is like a new deal, requiring financing and government permits, and allowing foreigners to hold something back that the President might want in the hope he will shape public policy in their favour.

Trump's administration addressed one potential conflict when the Justice Department said on Saturday that federal anti-nepotism laws do not prevent the President from appointing his son-in-law to his administration. That clears the way for Jared Kushner, Ivanka Trump's husband, to take a post as a senior adviser.

Federal anti-nepotism laws prevent relatives from being appointed to government positions. The Trump transition team argued, and a career Justice attorney agreed, that the laws apply to jobs in federal agencies, not White House posts.