Democratic Sen. Bob Casey asked a government ethics office Monday to assess whether President Donald Trump's business dealings make his administration vulnerable to conflicts of interest.

"President Trump has exposed his administration to possible conflicts of interest on an unprecedented scale," the Pennsylvania lawmaker says in a letter to the Office of Government Ethics.

Casey asked whether any of Trump's foreign business deals could violate the Emoluments Clause of the Constitution, which prohibits U.S. officeholders from accepting gifts from foreign countries.

The White House did not immediately respond to a request for comment.

Walter Shaub, the director of the ethics office, strongly criticized Trump earlier this year for not divesting from his businesses. Shaub said Trump was breaking decades of tradition by presidents who set up blind trusts for their assets.

Casey cited several of Trump's foreign business deals as examples that could present conflicts of interest. He cited an Associated Press report that the Trump Organization is returning to a long-dormant licensing deal involving a beachfront luxury resort in the Dominican Republic, despite Trump's promise not to do any new foreign deals.

The deal had been on hold for years before being revived this year.

The Office of Government Ethics advises executive agencies on potential conflicts of interests. But the agency does not investigate complaints and does not have the authority to prosecute offenses.

The office also works out ethics agreements with members of the president's Cabinet. The president, however, is not obligated to conform to an ethics agreement.