Janet Yellen, the outgoing US Treasury secretary, has warned that the next administration's plan to extend the 2017 Republican tax cuts could upset the financial marekt and worsen an already challenging US fiscal outlook. "The projected fiscal path under the current budget policy is simply not sustainable, and failure to act or take action that exacerbates the projected deficit could have dire consequences," Yellen said on Wednesday in what could be her last speech in office. In a speech delivered at the Association for Business Economics in New York, Yellen said extending her first-term tax cuts as planned by Trump "could undermine the strength of our nation, from the resilience of the Treasury market to the value of the dollar, and even trigger a debt crisis down the road". She also said that such "bad economic decisions" would affect the long-term economic outlook and place a heavy burden on the next generation.