Sen. Carl Levin, D-Mich., opened the Senate Armed Forces Committee during which U.S. Army Gen. David Petraeus and U.S. Ambassador to Iraq Ryan Crocker offered their assessments on security, political, diplomatic and economic fronts.

Petraeus recommended beginning an assessment and evaluation of further reductions in U.S. troop presence after the current drawdown ends this summer.

Levin said an "open-ended pause in troop reductions ... would simply send the wrong message to Iraqi leaders."

Instead, the United States must pressure Iraqis to settle their political differences, pay for their reconstruction and take a lead in conducting military operations.

"Promptly shifting responsibility to the Iraqis for their own future politically, militarily and economically is the best hope for a successful outcome in Iraq and represents finally an exit strategy for most of our troops," Levin said.

Sen. John McCain, R-Ariz., ranking minority member, said a "reckless and irresponsible" troop withdrawal would "constitute a failure of political and moral leadership."

"I do not want to keep our troops in Iraq a minute longer than necessary to secure our interest there," McCain said. "Our goal ... is an Iraq that no longer needs American troops."