US Secretary of State Colin Powell has said the conflict between US forces and insurgents in Iraq is getting worse.
Powell says he wants people to vote across Iraq
He told US TV networks that militants wanted to disrupt elections in January - but the US would increase efforts to defeat them.
However, he added that Washington remained determined to hold elections across the whole country.
This comes after Defence Secretary Donald Rumsfeld suggested that violence could prevent voting in some areas.
On Thursday Mr Rumsfeld told a Senate committee that a partial election - leaving out the most troublesome regions - would be "better than not having an election".
Mr Powell on Sunday recognised that the US was "fighting an intense insurgency".
"Yes it's getting worse and the reason it's getting worse is that
they are determined to disrupt the election," he told ABC's This Week programme.
Mr Powell said polling stations may be shot at, but added that Washington's aim remained "to give everybody the opportunity to vote... to make the election fully credible".
Meanwhile, the commander of US troops in the Middle East, Gen John Abizaid echoed Mr Rumsfeld in an interview with NBC's Meet the Press programme, saying Iraqis may not be able to go to the polls in some places.
But he predicted voting would take place in the "vast majority of the country".
Insurgents in Falluja are being targeted by US air strikes
In Iraq itself, three people have been killed in fighting between US forces and insurgents in Ramadi, west of Baghdad.
American marines shelled a district of the city after coming under attack from mortars, witnesses said. All the casualties are reported to be Iraqi.
In a separate incident, a number of US and Iraqi soldiers were reported injured when two car bombs exploded on the outskirts of the rebel-held city of Falluja.
A US military official said militants tried to ram the cars into an Iraqi National Guard compound in the town of Kharma.
Falluja itself is currently quiet after a second night of air raids by US forces. Doctors say a total of 15 people, including women and children, were killed.
In other developments:
- the US military announces that a senior member of the Iraqi National Guard had been arrested on Thursday for suspected links with insurgents.
- there are reports of several deaths in an attack on a petrol convoy in Latifiya, south of Baghdad
- a rocket attack in the centre of Baghdad is reported to have killed one person
- a delegation from Britain's Muslim Council is in Baghdad to try to secure the release of a British man, Ken Bigley, held hostage for more than a week
The latest air raids on Falluja form part of efforts by US forces to flush terror suspect Abu Musab al-Zarqawi and his fighters out of the city.
The US accuses the Jordanian-born militant, who heads the Tawhid and Jihad movement, of leading al-Qaeda operations in Iraq and for being behind numerous car bombings and kidnappings.
This week his group beheaded two American hostages and has threatened to kill Kenneth Bigley.
US officials have offered a $25m bounty for information leading to Zarqawi's capture.
News agencies quoted an unnamed senior US official as saying on Sunday that more than 100 militants loyal to Zarqawi had been killed in Falluja in the last four weeks.