Key members of the U.S. federal judiciary warned on Tuesday of a rising number of threats directed at their colleagues and described calls to impeach judges over their rulings "concerning" as some Republican lawmakers push to remove jurists who have blocked U.

Two members of the advisory body for the federal judiciary warned Tuesday about Congress turning to impeachment of judges if lawmakers are unhappy with decisions. Four impeachment resolutions have been filed against three judges this year,

Top U.S. federal judges have raised alarms over increasing threats and calls for impeachment against their colleagues. U.S. Circuit Judge Richard Sullivan, chair of the Judicial Conferences security committee,