Iraqi lawmakers close to the new ruling coalition reacted frostily yesterday to a blunt demand from Secretary of Defense Rumsfeld to drop plans to purge former Saddam loyalists from the armed forces.

Many legislators from the Shiite majority that dominated January’s elections have said ex-Baathists must be culled from the army and police.

But Washington fears that such a move would look like retribution against Iraq’s Sunni Arab minority, give rise to accusations of nepotism, and rob the security services of much-needed expertise.

The issue is likely to test American relations with Prime Minister al-Jaafari’s incoming government, which will take power once a Cabinet is named in the next few weeks.

“We have an opportunity to continue to make progress politically, economically,” Mr. Rumsfeld said before arriving in Baghdad on a surprise visit. “Anything that would delay or disrupt that as a result of turbulence, or lack of confidence or corruption in government, would be unfortunate.”

Despite the smiles as he met Mr. Jaafari and President Talabani, there was a distinct mood of irritation among Shiite members of the United Iraqi Alliance, the main bloc in the new ruling coalition.

“We have reservations about his opposing a purge before the government has even been officially created,” said Saad Qindeel, the head of the political bureau of the Supreme Council for Islamic Revolution in Iraq, the largest party in the alliance.

“What we have called for is to purge the security organs of terrorist infiltrators and insurgents. Most of them happen to be Baathist elements.”

The Shiite majority was brutally suppressed by Saddam Hussein’s security forces and resent what they see as American interference on a subject they feel passionate about.

But American officials say they are keen that the new government does not make the same mistakes as they did.

After toppling Saddam, the former American proconsul Paul Bremer disbanded the Iraqi army, a decision now widely considered to have been a major factor in the violence that grips the country. Disgruntled soldiers, robbed of their livelihoods, flocked to the insurgency.

The outgoing prime minister, Ayad Allawi, went some way to redress the balance, by rerecruiting some former soldiers.

Even before Mr. Rumsfeld’s brief visit, Washington had placed considerable pressure on Mr. Jaafari to abandon a purge.

“We’re talking to these people and making them aware of our concerns,” an American official said. “When we say something and we repeat it, we mean it seriously.”

With the Iraqi security forces growing in proficiency and size – at close to 150,000, the number of Iraqi servicemen now nearly matches the coalition presence – America can begin to contemplate withdrawing some troops. Those plans received a setback yesterday, however, as Poland announced it would pull its troops out by the end of the year.

With 1,700 soldiers, the Poles are not only the fourth-largest contingent, they also command three provinces – the only foreign force to control a region apart from the Americans and British.

Several foreign contributors to the multinational force have either pulled out of what has been dubbed the “Coalition of the Wilting” or have signaled their intention to do so.

Iraq’s future is considered to depend primarily on an inclusive political process, thought only to be achievable by the participation of Sunni Arabs. Most of the minority boycotted the election.

The new government is trying to persuade Sunnis to participate in the writing of a new constitution, meant to be in place by August 15, to ensure their participation in full elections timed for December.

But wrangling over Cabinet posts has raised the prospect of both constitution and election being delayed by six months.