Democratic leaders in Congress have stepped up pressure on the US Treasury department to consider assisting the ailing US car industry through the $700bn financial rescue plan enacted last month.

In a letter to Hank Paulson, Treasury secretary, sent on Saturday, Harry Reid, Senate majority leader, and Nancy Pelosi, House speaker, said after meeting representatives from the top three carmakers on Thursday they were "convinced that our nation's automobile industry, the heart of our manufacturing sector, and the jobs of tens of thousands of Americans are at risk".