The U.S. 30-year Treasury bond extended prices gains to a point in Thursday afternoon trade as stock market losses whetted investors' appetite for safe-haven U.S. government debt.

Thirty-year bonds were up 1-6/32, their yields falling to 2.96 percent from 3.02 percent late on Wednesday.

Meanwhile, major stock indexes were all lower, with the S&P 500 stock index down nearly 2 percent and the Nasdaq composite index down 2.2 percent.