Republican Sens. Ron Johnson (Wis.) and Chuck Grassley (Iowa) wrote a letter to Secretary of State Mike Pompeo on Thursday, requesting that the State Department release all records pertaining to the agency's interactions with Hunter Biden and his associates during the Obama administration.

What are the details?

Sen. Johnson, chairman of the Homeland Security and Government Affairs Committee, and Sen. Grassley, head of the Committee on Finance, asked for all information on interactions related to Hunter Biden, several of his business associates, and affiliated business ties including those with Ukrainian natural gas firm, Burisma Holdings, where he was a board member until this year.

The senators cited newly released State Department emails obtained through a Freedom of Information Act lawsuit, that were published and reported on by investigative journalist John Solomon and showed numerous meetings were set up between individuals linked to Biden and Burisma with State Department officials during the Obama administration — when Biden's father, Democratic presidential candidate Joe Biden, was vice president.

Johnson and Grassley wrote that they were seeking "to better understand what actions, if any, the Obama administration took to ensure that policy decisions relating to Ukraine and Burisma were not improperly influenced by the employment and financial interests of family members."

Anything else?

Hunter Biden's employment with Burisma during the time his father was the Obama administration's point man in Ukraine has fallen under greater scrutiny in recent months, after Democrats launched an impeachment inquiry into President Donald Trump for allegedly threatening to hold up aid to Ukraine unless a corruption investigation into Burisma was reopened.

The Ukrainian government launched a corruption probe into the gas firm in 2014, and former Vice President Biden boasted last year that he threatened to withhold $1 billion in aid from the country unless it fired the prosecutor investigating the allegations against his son's firm.

The Bidens have repeatedly denied any wrongdoing in the scandal, and President Trump has maintained his own innocence while insisting it is his responsibility to root out corruption from countries accepting U.S. assistance.