Trump and a number of administration officials have repeatedly stayed at Trump-owned properties during his presidency, raising concerns about whether the president has profited from his presidency. Legal observers have also questioned whether he has violated the Constitution’s emoluments clause, which prohibits federal officials from profiting from foreign or domestic government bodies.

“Citing security and logistical concerns, you and your Chief of Staff have made the claim that staying at President Trump’s resort in Doonbeg was necessary. I find it hard to believe that your office was unable to identify lodgings that could accommodate the security and logistical needs of your trip in the capital of Ireland, which houses among other locations the United States Embassy – where President Reagan stayed during his 1984 visit,” Sen. Gary Peters (D-Mich.), the top Democrat on the Senate Homeland Security Committee, wrote in a letter to Pence Thursday.

A top Senate Democrat wants to investigate whether Vice President Mike Pence’s taxpayer-funded stay at a golf club in Ireland owned by President Donald Trump was another “apparent conflict of interest” involving Trump, his administration and his business properties.

ASSOCIATED PRESS Speaking to reporters in Dublin, where Vice President Mike Pence spent the day, he spoke about his personal connection to the village of Doonbeg — the site of both the Trump International Golf Links & Hotel as well as family history.

In response to inquiries earlier this week, Pence’s office initially claimed that he stayed at Trump’s golf club at the “suggestion” of the president. Pence also described it as a “family” visit because his cousin runs a bar in Doonbeg, and his great-grandmother grew up there.

“I am alarmed that you elected to spend taxpayer dollars for travel and lodging at President Trump’s privately-owned property – located on the other side of the country, more than 180 miles away from your meetings with government officials in Dublin,” Peters wrote Thursday. “This raises serious concerns about wasteful expenditures and possible conflicts of interest related to taxpayer-funded travel by this Administration.”

Peters also attached a series of questions to Pence about the trip, including how much it cost taxpayers and the government, whether he was charged the regular rate or “a government rate,” and “whether any analysis was conducted to compare the full costs of travel — including lodging, security, and other travel costs – for staying in Doonbeg instead of Dublin during your official visit to Ireland.”

According to government watchdog group Citizens for Responsibility and Ethics in Washington (CREW), at least 250 Trump administration officials have made at least 630 visits to Trump-owned properties, most frequently his senior advisers, daughter Ivanka Trump and son-in-law Jared Kushner.

Trump himself spends many weekends at his golf clubs in Virginia, New Jersey or Florida, costing taxpayers more than $100 million so far. Attorney General William Barr is reportedly set to host a holiday party at Trump’s Washington hotel in December.

Pence’s office did not immediately respond to a request for comment on Peters’ letter, which was first obtained by ABC News.

On Wednesday, Trump said he had “no involvement” in Pence’s decision to stay at his golf club.

“From what I understood, he was going there,” Trump said. “Then I heard he was going there, but I didn’t ― it wasn’t my idea for Mike to go there. Mike went there because his family is there. That’s my ― that’s my understanding of it.”

Read the full letter below.