WASHINGTON — U.S. intelligence agencies are “urgently warning” private sector companies throughout the nation that Iranian actors “are conducting exploitation activity” that has resulted in “disruptions across several U.S. critical infrastructure,” according to a government notice reviewed by The Times.The Iranian cyber activity comes as President Trump is threatening to target Iran’s critical infrastructure in the coming hours, particularly its bridges and power plants.Iran’s attack targeted products by Rockwell Automation’s Allen-Bradley, one of the most widely used industrial automation brands, according to the notice, which said that cyber actors affiliated with Iran were exploiting “programmable logic controllers across U.S. critical infrastructure.”Tehran’s targeting...