The White House has expressed concern over reports that the US military is planting favourable stories about Iraq in the Baghdad press.
Iraqis will wonder whether they should trust what papers say
"We are seeking more information from the Pentagon," White House spokesman Scott McClellan said.
The reports, originally carried by the Los Angeles Times, said the Pentagon was secretly paying Iraqi papers to run articles praising US and Iraqi troops.
Many stories are being presented as independent accounts, the paper said.
"We're very concerned about the reports," Mr McClellan said on Thursday.
"We need to know what the facts are," he told reporters.
The US, Mr McClellan said, was "a leader when it comes to promoting and advocating a free and independent media around the world, and we will continue to do so".
He added: "We've made our views very clear when it comes to freedom of press."
Earlier, a US military spokesman in Baghdad, Maj Gen Rick Lynch, appeared implicitly to confirm the reports.
He said that Iraq's most- wanted militant Abu Musab al-Zarqawi, was also using the media
"He is lying to the Iraqi people. We don't lie - we don't need to lie," Gen Lynch said.
"We do empower our operational commanders with the ability to inform the Iraqi public but everything we do is based on fact, not based on fiction."
The Los Angeles Times alleged that stories about Iraq were written by US soldiers, and translated into Arabic by a defence contractor which helps place them in Baghdad papers.
Although many are basically factual, they only present one side of events and omit information that might reflect poorly on the US or Iraqi government, the newspaper said.
The BBC's Caroline Hawley in Baghdad says the allegations are an embarrassment to the American military at a time when it is trying to promote transparency in Iraq.