A telecom industry group Monday challenged “open Internet” regulations barring US broadband providers from separating online traffic into slow and fast lanes, hours after official publication of the order. The US Federal Communications Commission published its “net neutrality” order in the federal register earlier Monday, making the hotly contested rules effective June 12. USTelecom, a trade group that includes major broadband providers such as AT&T and Verizon, announced it had filed a lawsuit in federal court seeking to block implementation of the plan.