Top US Senate Democrats are asking the Trump Organisation to explain the company’s ties to China after reports from The New York Times that the US president’s company has a bank account there.

In a letter to Trump Organisation lawyer Alan Garten obtained by Bloomberg News, the senators asked for the name of the financial institution and for a detailed accounting of all the transactions between US President Donald Trump’s bank account and China since 2013.

The letter comes as Democrats are making their closing arguments to voters about why they should deny Trump a second term in the November 3 presidential election. Democrats said it is imperative that Congress understand the president’s financial entanglements in China, particularly after refusing to relinquish control of his company or publicly release his tax returns.

Trump has denied any wrongdoing and says that his Chinese bank account has been closed for years.

“I closed it before I even ran for president, let alone became president,” Trump said in the final presidential debate this month.

The letter, signed by Senate Minority Leader Chuck Schumer and Senators Ron Wyden and Sherrod Brown, requested more information about a entity controlled by the president’s company, Trump International Hotels Management, which The New York Times said paid US$188,561 in taxes to China between 2013 and 2015.

The senators asked for more information about how much that entity has earned in China and other foreign countries.

“It appears that in 2017, immediately after President Trump took office, Trump International Hotels reported an unusually large increase in revenue of US$17.5 million,” the senators said in the letter.

“This was reportedly followed by a US$15.1 million withdrawal by President Trump from the company’s capital account.”

The senators said it remains unclear where the money came from and how it was spent.

The lawmakers also asked for more information about trademarks the Chinese government has approved for entities owned by Ivanka Trump, the president’s daughter and a White House aide.

The lawmakers asked if the president has any ties to the accounts holding those trademarks.