Treasuries tumbled, with 30-year bonds on pace for their biggest two-day selloff in more than a year, after the European Central Bank's (ECB's) decision not to expand its stimulus program sparked a rout in global sovereign debt.

Long-dated securities, which have been outperforming in recent months, led losses for a second day after ECB President Mario Draghi said Thursday that officials didn't discuss an extension to the institution's asset-purchase plan, disappointing investors who had been speculating that more stimulus was imminent. Treasury 10-year yields rose to the highest since June as German 10-year bund yields turned positive for the first time since July.

While yields are still lagging below historical averages, they're quickly rising from record lows reached earlier this year, recalling the bond rout of 2015, which saw German 10-year yields climb more than a percentage point in less than two months. The selloff comes before Federal Reserve officials meet Sept. 20-21 to decide the path of U.S. interest rates, and as the Treasury plans three fixed-rate note and bond auctions early next week.