US long-term borrowing costs have climbed to their highest level in almost 25 years as a sell-off in the Treasury market picked up pace. The yield on the 30-year US Treasury rose 0.06 percentage points in afternoon trading in New York on Tuesday to 5.62 per cent. This was its highest level since June 2002. The 10-year Treasury yield also rose as much as 0.05 percentage points to 5.29 per cent, taking benchmark US borrowing costs to another post-2007 high.