By Alina Selyukh WASHINGTON (Reuters) – Over 100 leading technology companies, including Google Inc, Facebook Inc, Twitter Inc and Amazon.com Inc, have written to U.S. telecom regulators to oppose a new \net neutrality\ plan that would regulate how Internet providers manage web traffic. The letter to Federal Communications Commission Chairman Tom Wheeler and the agencys four commissioners, warning of a \grave threat to the Internet,\ came amid calls for a delay in a vote on the plan scheduled for May 15. \Rushing headlong into a rulemaking next week fails to respect the public response to his (Wheelers) proposal,\ FCC Commissioner Jessica Rosenworcel said on Wednesday in remarks prepared for delivery to an industry meeting. FCC spokesman Neil Grace said Wheeler still intends to put forward his proposals for public comment next week, as planned, as part of a \robust public debate\ on the Internet.