April 8 (Bloomberg) -- Army General David Petraeus told lawmakers today that progress in Iraq is too ``fragile and reversible'' to allow U.S. troop levels to fall below about 140,000 earlier than September.

Petraeus, testifying before the Senate Armed Services Committee in Washington, recommended a 45-day evaluation after the final brigade from last year's ``surge'' of troop reinforcements into Iraq is withdrawn in July. Only after that period can officials begin to consider further withdrawals, he said.

``This approach does not allow establishment of a set withdrawal timetable,'' Petraeus, 55, said. ``However, it does provide the flexibility those of us on the ground need to preserve the still-fragile security gains our troopers have fought'' to attain.

Iraq's stability, Iran's influence on the country and the ultimate cost of the occupation to the U.S. in lives, money and military readiness were the major issues lawmakers debated during the hearing and a later session of the Senate Foreign Relations Committee.

Democrat Carl Levin, the Armed Services Committee's chairman, immediately criticized Petraeus's proposal, calling it a ``a plan which has no end.'' Levin, a senator from Michigan, said Iraqis had failed to use the drop in violence attributed to the surge to push toward political unity and away from dependence on American forces and on U.S. reconstruction funding.

Appeals for Time

Richard Lugar of Indiana, the top Republican on the Foreign Relations Committee, echoed Levin's comments later in the day, saying appeals for more time are insufficient.

``We need a strategy that anticipates a political endgame and employs every plausible means to achieve it,'' Lugar said.

Petraeus was asked by Foreign Relations Committee Chairman Joseph Biden to estimate on a scale from 1 to 10 how far the U.S. has progressed toward conditions that would permit a major drawdown of forces. The general answered, ``6 or 7.''

A possible future U.S. commander-in-chief, Senator Barack Obama of Illinois, said he is looking for a ``successful'' resolution to the conflict with a specific timetable for withdrawal.

``There's a bipartisan consensus that we have finite resources,'' said Obama, a candidate for the Democratic presidential nomination who serves on the Foreign Relations Committee. ``Our military is overstretched and the Pentagon has acknowledged that.''

Fewer Troops

Obama said a diplomatic initiative is needed to resolve the issues of Iran's role in Iraq. He asked whether the status quo in Iraq would be sustainable with just 30,000 American troops.

The U.S. currently has more than 150,000 troops in Iraq. As of today, 4,017 U.S. personnel have died in Iraq since the conflict began in March 2003, and 29,676 Americans have been wounded, according to the Defense Department.

Senator John McCain of Arizona, defended President George W. Bush's strategy, saying the U.S. is no longer ``staring'' at defeat in Iraq.

``Today it is possible to talk with real hope and optimism about the future of Iraq,'' said McCain, the top Republican on the panel and his party's presumptive nominee for president. ``An American failure would almost certainly require us to return to Iraq or draw us into a wider and far, far costlier war.''

Outburst at Hearing

McCain's questioning was interrupted by an unidentified man shouting ``bring them home'' seven times before police officers removed him from the room.

Democratic presidential candidate Hillary Clinton told Petraeus and U.S. Ambassador to Iraq Ryan Crocker, who sat alongside the general, that the Iraq strategy hasn't produced the ``promised results'' and the U.S. should begin the ``orderly'' withdrawal of forces.

Clinton objected to a Bush administration plan to negotiate a long-term agreement with Iraq on the presence of American troops without submitting the accord to Congress for approval.

Iraq's ambassador to the U.S., Samir Sumaida'ie, said any candidate talking about troop withdrawal will be faced, as president, with the reality that seeing the mission through is in the interests not only of Baghdad but also of Washington.

``This is a long recovery from what was a terminal illness,'' Sumaida'ie said today at a forum in Washington organized by the Center for Strategic and International Studies.

Consequences of Invasion

Anthony Cordesman, an analyst at the Washington-based center, said the U.S. has a moral and ethical responsibility for the consequences of its invasion.

About 10 percent of the country's population has come to adulthood in the past five years, and half a generation of Iraqis live with a lack of security and an unemployment or underemployment rate of 50 percent, he said at the forum.

``Regardless of the reasons we went to war or what we may individually think of the war, we cannot afford to ignore the fact that our actions have impacted on an entire nation,'' Cordesman said.

Beginning two days of testimony before Congress, Petraeus said Bush's deployment of about 21,000 more U.S. troops last year helped quell violence in Iraq.

Basra Performance

Under questioning, Petraeus described as disappointing the performance of some Iraqi troops who were sent last month to defeat Shiite militias in the southern city of Basra. The offensive ``could have been better planned'' by the Iraqis, the general said.

Crocker told lawmakers that the trend in Iraq is ``positive'' as Iraqi politicians overcome ``sectarian barriers'' to pass needed legislation, including a budget.

``The strategy that began with the surge is working,'' Crocker said. ``This does not mean, however, that U.S. support should be open-ended or that the level and nature of our engagement should not diminish over time.''

Both Petraeus and Crocker warned lawmakers about Iranian meddling in Iraq. Petraeus said Iranian-backed militia groups ``pose the greatest long-term threat to the viability of a democratic Iraq.''

``The extent of Iran's malign influence was dramatically demonstrated when militia elements armed and trained by Iran clashed with Iraqi government forces in Basra and Baghdad,'' Crocker said.

Oil Prices

Senators criticized Iraq for not taking a greater role in paying for reconstruction, particularly with oil prices near record highs.

``Sky-rocketing oil prices have swelled Iraqi oil revenues beyond all expectations,'' Levin said. ``But Iraqi leaders and bureaucrats aren't spending their funds.''

In response, Crocker pledged that ``the era of U.S.-funded major infrastructure projects is over'' as Iraq begins to use more of its own money to pay for rebuilding.

Iraq's Oil

Iraq pumped 2.38 million barrels of crude a day last month, according to Bloomberg estimates. That output is among the highest recorded since the 2003 invasion of Iraq.

Republicans, who generally supported Petraeus at the hearing, expressed some disappointment with the performance of Iraqi forces.

Virginia Republican John Warner, a former chairman of the committee, interrupted Petraeus during a long answer about whether the war was making the U.S. safer.

``My time on the clock is moving pretty quickly,'' Warner said. ``Can you now, just in simple language, tell us, yes, it is worth it and it is making us safer here at home?''

``I do believe it is worth it,'' Petraeus replied.

To contact the reporters on this story: Nicholas Johnston in Washington at njohnston3@bloomberg.net; Ken Fireman in Washington at kfireman1@bloomberg.net

Last Updated: April 8, 2008 18:02 EDT