(CNN) The White House is rejecting a request from congressional Democrats to obtain documents tied to President Donald Trump's communications with Russian President Vladimir Putin.

In a letter to three Democratic committee chairmen, White House counsel Pat Cipollone said that the courts have long established that presidential communications with foreign leaders are protected and confidential.

"The President must be free to engage in discussions with foreign leaders without fear that those communications will be disclosed and used as fodder for partisan political purposes," Cipollone wrote in the letter, obtained by CNN. "And foreign leaders must be assured of this as well."

Three Democrats -- House Intelligence Chairman Adam Schiff, House Foreign Affairs Chairman Eliot Engel and House Oversight Chairman Elijah Cummings -- sent a letter to the White House earlier this month asking for information on communications between Trump and Putin.

The Democrats say they're investigating whether the President his associates attempted to conceal or misrepresent the nature of Trump's contacts with Putin. Schiff, Engel and Cummings are still mulling whether to subpoena the translators of Trump's meetings with Putin, following reports that Trump kept his aides in the dark about the meetings and took his interpreter's notes following his 2017 meeting with Putin in Germany.

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