On 2 January, two Reuters journalists and their driver were detained for 72 hours near the restive town of Falluja, west of Baghdad, by US troops after being mistaken for enemy fighters, the company said in a statement.
Following their release, the international news agency lodged a formal complaint with the US military, attesting to their alleged mistreatment in detention.
"Unfortunately no progress has been made. Immediate action is necessary to address these issues," it said, in a copy of a letter sent to the US defence department.
After their arrests, Brigadier General Mark Kimmitt, the coalition's deputy director of operations, said five people wearing black vests marked "press" fired at and were then chased by US troops, who captured four of them.
Two Reuters cameramen, Ukranian-born Taras Protsyuk, 35, and Palestinian Mazin Dana, 43, were also killed by US troops while covering the Iraq war in 2003.
The letter, signed by David Schlesinger, the Reuters global managing editor, appeals for a copy of a US military report into the death of Dana, who was shot on 17 August 2003. It said the report was promised several months ago.
Situation not improving
"The safety of journalists in Iraq is not improving," Schlesinger said in the statement.
"We think it absolutely necessary that this be addressed... To achieve this we need a genuine commitment from the military to engage in constructive dialogue and quickly resolve outstanding issues," he added.
(File picture) Dana himself had
protested at killing of journalists
Reuters last complained to US Defence Secretary Donald Rumsfeld in September, accusing the Pentagon of failing to provide adequate information about the investigation into Dana's death.
A military investigation cleared US troops who mistakenly shot and killed Dana as he was videotaping near a US-run prison outside Baghdad on 17 August.
Protsyuk died on 8 April when a US tank opened fire on Baghdad's Palestine Hotel, a day before the fall of the Iraqi capital to the US-led occupation forces.
Dana was killed days after a controversial military investigation cleared US forces of improper conduct in firing at the hotel, which was filled with foreign journalists.
Press groups have expressed deep concern over the killing of Dana, who won an International Press Freedom Award in 2001 from the Committee to Protect Journalists for his work in the West Bank.