The Federal Reserve's top Wall Street cop Michael Barr and other bank regulators will defend plans to hike U.S. bank capital requirements when they appear before Congress this week as they come under increasing pressure from many lawmakers to rein in their efforts. Barr, the Federal Deposit Insurance Corporation's Martin Gruenberg and acting Comptroller of the Currency Mike Hsu will appear before the Senate Banking Committee on Tuesday at 10 a.m. ET (1500 GMT) and the House of Representatives Financial Services Committee on Wednesday at 9:30 a.m. ET (1430 GMT).