The top U.S. military commander in Iraq and the U.S. ambassador told Congress Tuesday that progress in Iraq is "fragile" and "reversible," and called for continuing U.S. commitment, including an open-ended pause in U.S. troop withdrawals after the last of the surge forces leave in July.  VOA's Al Pessin reports.

General David Petraeus and Ambassador Ryan Crocker used the words "fragile" and "reversible" several times during their lengthy testimony.  Because of that, General Petraeus says he told President Bush he does not want to decide at least until sometime in September whether there can be further U.S. troop withdrawals without jeopardizing fledgling security gains and political progress.

"I recommended to my chain of command that we continue the drawdown of surge combat forces and that upon withdrawal of the last surge brigade combat team in July we undertake a 45-day period of consolidation and evaluation," he said.  "At the end of that period, we will commence a process of assessment to examine the conditions on the ground, and over time determine when we can make recommendations for further reductions."

Some members of the Senate Armed Services Committee objected to what they see as an "open ended" pause in U.S. withdrawals.  But General Petraeus said he needs time to assess the impact of the loss of one quarter of his U.S. combat power and that further reductions must be based on the situation at the time.

"The operational considerations include recognition that the military surge has achieved progress, but that that progress is reversible," he added.  "Iraqi security forces have strengthened their capabilities, but still must grow further.  Withdrawing too many forces too quickly could jeopardize the progress of the past year.  And performing the necessary tasks in Iraq will require sizable conventional forces, as well as Special Operations Forces and advisor teams."

He did not dispute one senator's suggestion that the pause could be several months long.  The general expressed specific opposition to the desire by some members of Congress for a more extensive withdrawal plan, which they believe would put pressure on the Iraqi government to move faster in developing its security forces and reaching political accommodation on key issues.

"This approach does not allow establishment of a set withdrawal timetable," he explained.  "However, it does provide the flexibility those of us on the ground need to preserve the still-fragile security gains our troopers have fought so hard and sacrificed so much to achieve."

General Petraeus said the threat from Sunni militants of al-Qaida in Iraq has been significantly reduced, but the group is still lethal.  He also singled out Iran for playing what he called a "particularly damaging" role in Iraq by supporting and "directing" violent breakaway Shiite groups, which he called "the greatest long-term threat to the viability of a democratic Iraq."

At the same hearing, Ambassador Ryan Crocker said almost everything about Iraq is hard.  But he said success is closer than it was last September, the last time he and General Petraeus testified.

"Developments over the last seven months have strengthened my sense of a positive trend," he said.  "Immense challenges remain and progress is uneven and often frustratingly slow.  But there is progress.  Sustaining that progress will require continuing U.S. resolve and commitment.  What has been achieved is substantial, but it is also reversible."

Ambassador Crocker warned skeptical members of Congress that the United States will be judged more by what happens in Iraq in the coming years, than by what has happened in the five years since the U.S.-led invasion.  He said progress is "real," but "still fragile," and urged the Congress to "stay with" the "current course."