US Central Command, in a summary of its probe released on Tuesday, said occupation troops acted "in an appropriate" manner when they pounded the Palestine Hotel in Baghdad on 8 April, killing two television cameramen.
Military officials said they had cleared troops of any wrongdoing in firing a tank shell into the 15th-floor balcony of the hotel. It was well-known as the main base for dozens of journalists in Iraq, covering the war.
Reuters camerama, Ukrainian Taras Protsyuk and Spanish cameraman, Jose Couso of Telecinco were both killed in the attack which also left three other Reuters journalists wounded.
Couso's brother, Javier, criticised the investigation's findings on Wednesday as a "lie" which sought to cover up what he described as a "war crime".
"We will continue to demonstrate at the headquarters of the (ruling) popular party and outside the US embassy and will pursue our action right all the way to the courts," he said.
Couso's family blasted what they said was the reluctance of Spanish Prime Minister Jose Maria Aznar's government to plead their case.
Spain was a champion of the US-British war against Iraq. Madrid has not made any official comment.
A spokesman for Couso's former employer Telecinco said the broadcaster had no comment on the findings.
Reuters spokeswoman, Susan Allsopp, said the international news agency was anxious to see the full report on the attack before providing a more detailed response.
US forces fired shells at the hotel because they believed an enemy “hunter/killer team” were attacking them from an upper floor of the hotel, according to Centcom’s news release.
Tariq Ayoub: Killed when a US
missile slammed into offices
“The action was fully in accordance with the rules of engagement,” it claimed.
American troops apparently got possession of “enemy radio” and monitored transmissions that indicated a spotter across the Tigris River was directing heavy fire at them.
In Kiev, the Ukrainian Foreign Ministry said it had been informed that “the shot was fired in self-defence and in complete conformity with the rules of combat”.
A separate investigation by the Committee to Protect Journalists (CPJ), a watchdog group, concluded in May the attack was avoidable.
The Pentagon had earlier expressed regret for the deaths, but said it had repeatedly warned reporters that the area was dangerous.
At least 14 journalists have been killed in Iraq, including Aljazeera cameraman Tariq Ayoub, since the start of the war in March.