The acting director of the Office of Government Ethics said some of President Donald Trump's business deals "raise serious concerns," but the agency doesn't have the authority to investigate.

Congressional Democrats are concerned about an Indonesian real estate development with Trump-brand properties receiving $500 million in loans for from the Chinese government.

The ethics office's response says the Constitution's Emoluments Clause, which prohibits any person holding office cannot accept a gift from a foreign power without congressional consent, does not fall under the office's authority.

The acting director of the Office of Government Ethics said some of President Donald Trump's business deals "raise serious concerns," but the agency lacks the authority to investigate, The Washington Post reported.

In a letter responding to congressional Democrats who had requested an ethics investigation, David Apol, who heads the ethics office, said he agreed Trump's dealings were concerning. But he said the president is exempt from the conflict-of-interest laws that govern other federal employees' business deals.

Apol added that Congress and voters are the ones with the authority to hold the president accountable.

"Under the Constitution, the primary authority to oversee the President's ethics rests with Congress and ultimately, with the American people," he wrote.

The 66 lawmakers had written to the office in May concerning an Indonesian real estate development, which includes include several Trump-brand properties, that would receive $500 million in loans from the Chinese government, according to the South China Morning Post.

Shortly after the Chinese loans were reported, Trump announced a deal to revive the Chinese telecom firm ZTE. The decision was widely criticized after it was announced earlier this month, with Sen. Minority Leader Chuck Schumer saying it was "helping make China great again."

The Democrats pointed to the development loan as possibly qualifying as a violation of the Constitution's emoluments clause, which dictates any person holding office cannot accept a gift from a foreign power without congressional consent.

But Apol said the Justice Department is solely responsible in investigating any possible violation of the emoluments clause.

Apol also responded to the lawmaker's inquiry about possible conflict of interest in Trump's decision to protect Chinese tech giant ZTE from steep sanctions, saying the rules in question apply only to administration members, not the president or vice president.

This is not the first time the legitimacy of a Trump Organization deal has been questioned since Trump took office. Most recently, a letter was revealed in April from a Trump Organization-affiliated law firm to Panama's president that experts told Business Insider was a "not so subtle attempt" to use the presidency for "personal gain."

"It is essential to the success of our republic that citizens can trust the decisions made by government leaders are motivated by the public good and not by personal interests," Apol wrote in his letter.

Though the rules governing conflicts of interest among federal employees do not apply to the president, Apol wrote the office "has consistently held the President should conduct himself 'as if'" they do.