"We don't want any delays," Rumsfeld told reporters in Baghdad on Wednesday.
Rumsfeld said that he felt a delay would be wrong and that Washington, with troops in the line of fire, had an interest in pressing Iraqis to reach a deal.
"(A delay) would be very harmful to the momentum that's necessary. We have troops on the ground there. People get killed," he said. "It's time for compromise. That's what politics is about."
Rumsfeld also said Iraqi leaders must take a more aggressive stance against what he called harmful interference from neighbouring Syria and Iran.
Rumsfeld arrived unannounced in Baghdad on Wednesday with a series of messages for the country's interim leaders, suggesting a heightened sense of urgency in US President George Bush's administration to make faster strides on the political and security fronts so US forces can eventually leave.
He said he would be pushing the Iraqis to provide more people who could be trained by US personnel to handle the growing number of detainees in the country, now estimated to number at least 15,000.
With a permanent Iraqi government scheduled to take power in January, after adoption of a constitution and an election in December, they need trained prison guards "so that as soon as it is feasible we can transfer responsibility for Iraqi prisoners to the Iraqi government", he said.
Onus on Iraq
Rumsfeld has often criticised Iran and Syria for meddling in Iraq's affairs.
The unstable situation affects how
long US troops will stay in Iraq
In his remarks on Wednesday, he put the main burden on Iraqi leaders to do more to fix the problem.
"They need to be aggressively communicating with their neighbours to see that foreign terrorists stop coming across those borders and that their neighbours do not harbour insurgents and finance insurgents," he said.
Rumsfeld singled out Syria and Iran as troublemakers for the fledging government in Baghdad.
The future course of their relations will help determine when Iraq will be stable enough to fight the "insurgency" on its own, he said.
"[Iraqi leaders] need to be aggressively communicating with their neighbours to see that foreign terrorists stop coming across those borders"
US defence secretary
"Their efforts to destabilise the situation in Iraq: Does it increase or decrease?" he asked.
That is among the many unknowns that make it impossible to predict when Iraq's own security forces will be strong and reliable enough to allow American troops to begin leaving, the defence chief added.