High-wire talks between striking US workers and automotive giants are in a “critical phase,” Jeep-maker Stellantis said Saturday, as politicians staked out positions on a labor issue that could have national impact. Stellantis, together with fellow “Big Three” automakers General Motors and Ford, was hit Friday by a limited strike — but one the United Auto Workers (UAW) warns could spread. Both sides issued cautious statements Saturday. “Our bargaining team continues to work days, nights and weekends” in pursuit of a “reasonable” solution, said the statement from Stellantis, which was formed by the merger of Fiat Chrysler and the French PSA Group. But the automaker warned that if talks took a bad turn, the outcome “will take us backward and endanger the long-term competitiveness of our Company, negatively impacting our workers and our communities.” There was no immediate formal response from the union, but a UAW source told AFP, “we had reasonably productive conversations with Ford today.” Only about 12,700 of the UAW’s 150,000 members are currently on strike. But with workers at all of the Big Three coordinating strike action for the first time — including a demand for pay increases of 40 percent over a four-year contract — the automakers could face a far more disruptive stoppage.