US: The Senate armed services committee has called senior Pentagon officials to a closed-door session to explain why the US military is planting paid articles in Iraqi newspapers.
The White House has also expressed concern about the programme, in which articles written by US military were translated into Arabic and given to advertising agencies for placement in Iraqi papers.
Senate armed services committee chairman John Warner told Pentagon officials he wanted to hear a full description and justification of the programme.
"I am concerned about any actions that may undermine the credibility of the United States as we help the Iraqi people stand up as a democracy. A free and independent press is critical to the functioning of a democracy," he said.
Maj Gen Rick Lynch, the top US military spokesman in Iraq, initially refused to discuss the programme. He later justified it on the basis that Abu Musab al-Zarqawi, the al-Qaeda leader in Iraq, uses the news media to advance his terrorist campaign.
"We don't lie. We don't need to lie. 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," Maj Gen Lynch said.
The Los Angeles Times reported this week that Lincoln Group, the public relations firm employed by the US army in Iraq, produced television ads encouraging Sunnis to embrace the political process without indicating that they were funded by the US.
A state department spokesman said the US was helping Iraqi journalists to learn about ethics and proper journalistic practice.
"This is a country where free media didn't exist for decades, so they are learning. We think it's important to assist them in that," he said.