WASHINGTON: A group of US senators wants Congress' watchdog agency to investigate whether controls on humanitarian aid deliveries by Israel and other foreign governments violate US law, according to a letter seen by Reuters. The six senators - Chris Van Hollen, Dick Durbin, Jeff Merkley, Bernie Sanders, Elizabeth Warren and Peter Welch - wrote to Comptroller General Gene Dodaro asking him to launch an investigation by the nonpartisan Government Accountability Office of the US government's