Speaking from the southern Japanese island of Okinawa, Donald Rumsfeld said a transitional government would have no bearing on the US military presence in the country.
"This has nothing to do with coalition troops in Iraq," Rumsfeld told reporters. "The timetable... relates to the governance aspect of the country and not the security aspect, which run on a separate track," he added.
Elections will be held in Iraq before the end of 2005, according to an agreement signed and announced on Saturday between US occupation administrator Paul Bremer, and Jalal Talabani - current chair of the interim Iraqi Governing Council.
Critics of Washington's policy towards Iraq said before the US-led invasion in April the Bush administration intended to maintain a long term military presence in the oil-rich country.
At the time, Rumsfeld dismissed such suspicions as "inaccurate and unfortunate".
Rumsfeld’s comments come as he attempts to drum up support for shaky US-led occupation forces in Iraq and has been trying to sound upbeat about the situation there.
"The coalition is not shaken. We have 33 countries with forces on the ground in Iraq. Think of that. Thirty-three nations have forces on the ground in Iraq. It's a very broad coalition and it's doing very well," he said.
But at least 17 US soldiers were killed and five seriously injured late on Saturday when two US Black Hawk helicopters collided over northern Iraq as one was reportedly trying to evade an attacking missile.
Resistance grows despite the
increasing number of arrests
The crash west of the city of Mosul came shortly after the US-appointed Iraqi interim Governing Council announced elections would be held in Baghdad by the end of 2005.
Central Command officials declined to comment on the large number of fatalities, saying: "The incident is still under investigation, and the results will be released as soon as they are available."
In Baghdad, meanwhile, a US soldier was killed in the capital's al-Azamiyah district when a roadside bomb exploded as an army convoy drove by, also wounding two soldiers, the military said.
That death, along with those in the helicopter collision, raised to 178 the number of US troops killed in combat in Iraq since May 1, when Bush declared major hostilities over.
In Basra, a spokesman said occupation headquarters in the southern port city were still closed in the wake of the bloodiest resistance attack which killed 19 Italians and nine Iraqis in Nasiriyah on Wednesday.
"We are still not open. No Iraqi staff can come in" the huge compound overlooking Shatt al-Arab, once used as Saddam Hussein's official palace, Dominic d'Angelo told journalists.