Pennsylvania’s Sen. Bob Casey yesterday said testimony from the top U.S. military commander in Iraq delivered “more of the same,” and he challenged Gen. David Petraeus’ repeated claims of progress in the training of Iraqi security forces.

“I think you can understand,” Mr. Casey, a Democrat, told Gen. Petraeus during a Senate Foreign Relations Committee hearing, “not just the general frustration we feel, but, frankly, some of the skepticism we feel about your assertions in the past and your assertions here, as it compares to what the reality is.”

The commander was on Capitol Hill for a second round of all-day grilling by lawmakers about the success of the U.S. troop “surge” in Iraq, and Mr. Casey’s first chance to question him came after nearly four hours of testimony.