The commander of a United States tank unit that hit a Baghdad hotel, killing two cameramen during the battle for the Iraqi capital, says he was unaware the building was packed with journalists, according to a French magazine.

Reuters cameraman Taras Protsyuk and Jose Couso, a cameraman for Spanish channel Telecinco, were killed when a tank shell hit the 15th floor of the Palestine Hotel. Three other members of the Reuters team were wounded.

Captain Philip Wolford, who led the Abrams tanks defending a bridge near the Palestine Hotel on April 8, was quoted as saying he authorised the attack after his men spotted what appeared to be someone using binoculars on the roof of the same building.

"We had been engaged in fighting for several hours," Wolford said in an interview with French weekly Nouvel Observateur. "Firing was coming in the whole time, from that area as well as others. I returned fire. Without hesitation, that's the rule," he said, according to a Reuters translation of his remarks.

"I learnt 20 minutes later that we had hit...a hotel with journalists. I feel bad, my men feel bad," he added.

Asked whether he knew the building was being used as a base for most of the foreign media in Baghdad, Wolford said, "No, I hadn't received any information of that kind. "I can't imagine for an instant that any information sent by divisional headquarters would not have reached me."

A US official, requesting anonymity, said on Monday the incident was under investigation but declined specific comment on the magazine report.

Criticised by international media groups for the attack on the Palestine Hotel, the Pentagon initially said its troops were responding to sniper fire. But, journalists at the scene said they had heard no fire coming from the hotel.

Wolford said his unit had been under fierce attack as it defended the Jumhuriya Bridge and that it had been difficult to tell from where the incoming rockets or shells were being fired.

"On the bank I counted 20 or 30 teams of four men equipped with RPGs. Some of them were trying to board boats to get under the bridge where our position was. It was the biggest resistance we met entering Baghdad. Four of my men were hurt," he said.

The sighting of someone at the Palestine Hotel holding what appeared to be binoculars had suggested the fire was being directed from there.