WASHINGTON — Pulitzer Prize-winning journalist Seymour Hersh has alleged US Navy divers laid bombs that destroyed the Nord Stream 2 natural gas pipeline under the Baltic Sea last September, drawing a denial from the Pentagon Wednesday. Hersh, who scooped journalism’s top award more than five decades ago for exposing the My Lai massacre of Vietnamese civilians by US troops in 1968, cited an unnamed source in reporting on Substack that Americans planted remotely triggered explosives that wrecked three of the four pipelines built to carry natural gas from Russia to Europe. Hersh, 85, went on to claim that the Navy conducted the operation under the cover of a NATO maritime exercise, BALTOPS 22. In a short statement, Pentagon spokesman Marine Corps Lt. Col. Garron J. Garn told The Post “the United States was not involved in the Nord Stream explosion,” reiterating the Defense Department’s response to the same question in October. Swedish officials suspected the blasts were the result of “gross sabotage,” and some Western officials were quick to blame the attacks on Moscow as it blocked gas supplies to Europe in response to sanctions over last year’s invasion of Ukraine. “These are deliberate actions, not an accident,” Danish Prime…