U.S. Treasurys prices turned flat on Friday amid concerns about a Greek default spurred safety bids for U.S. government debt ahead of a Federal Reserve policy meeting next week.

Bonds rallied earlier as more bargain-hunters emerged and traders exited their earlier bearish bond bets, brushing off a 0.5 percent rise in U.S. producer prices in May and stronger-than-expected readings on consumer sentiment in early June.