Story highlights Kushner has denied any allegations that the Trump campaign colluded with Russia

The committee wants information about his communication with other campaign officials and his security clearance

Washington (CNN) Senate judiciary Chairman Chuck Grassley and ranking member Dianne Feinstein sent a letter Thursday requesting more information on President Donald Trump's son-in-law and adviser Jared Kushner related to his security clearance and questions over whether the Trump campaign colluded with Russia in the 2016 election.

The two senators specifically requested "transcripts from other committee interviews, additional documents from previous requests, communications with (former national security adviser) Michael Flynn and documents related to his security clearance," according to their statement.

Grassley, an Iowa Republican, and Feinstein, a California Democrat, sent a letter to Kushner's attorney, Abbe Lowell, requesting he provide access to the transcripts from Kushner's interviews with other congressional committees.

They wrote there are missing documents, such as emails to Kushner on WikiLeaks and a "Russian backdoor overture and dinner invite" that Kushner forwarded to another campaign official.

The two senators also requested all communications related to Flynn's termination as national security adviser and any emails between the two that contain keywords such as "Clinton," "WikiLeaks" and "Putin."

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