The second-ranking U.S. commander in Iraq says his forces are working to counter two new capabilities developed by insurgents - an improved ability to shoot down helicopters and a new type of bomb that involves deadly chlorine gas. The general spoke via satellite from Baghdad to reporters at the Pentagon, and VOA's Al Pessin reports.

US military Apache helicopter releases an anti-missile decoy flare over Baghdad, 15 Feb 2007

"We're seeing some common tactics, techniques and procedures, which I don't want to comment on," he said. "And so, we seem to be aware of what they're doing and we're trying to understand what those are, learn about it, so we can protect our aircraft, but more importantly, try to go after the cells."

General Odierno says coalition troops detained a man last week who they believe was a member of one of those cells, and made more arrests in raids during the last few nights. The general believes the cells are affiliated with the al-Qaida terrorist network. General Odierno says protecting the helicopters is essential for the coalition because it relies heavily on the aircraft for safe transport. He reports the coalition will fly about 400,000 hours of helicopter missions this year, nearly double the usage level of two years ago.

General Odierno also discussed the recent use of three chlorine gas bombs by insurgents. He says his forces discovered a supply of the gas at an insurgent bomb factory they raided on Tuesday near Fallujah, along with explosives, detonators and four vehicles in the process of being fitted with large bombs.

"What they're trying to do is try to adapt in such ways where they can continue to create instability," he added. "And that's what they're doing, especially with these chlorine VBIEDs [vehicle borne explosive devices]. That's just another way they're trying to adapt to cause some sort of chaos here in country."

The general says he has seen no indication that Iranians are involved in providing the chlorine bomb capability. Ten days ago, speaking on condition of anonymity, military officials in Baghdad accused top Iranian officials of providing bomb-making technology and materials to the Iraqi insurgents. On Thursday, General Odierno joined other top officials in saying he is not sure whether the Iranian involvement goes to the top of the Tehran government, as the briefers claimed.

On other issues, General Odierno said he supports Britain's decision to withdrawal 1,600 of its 7,000 troops from southern Iraq. He says Iraqi forces in the area have made "plenty of progress," and that soon they will be able to handle security on their own, with coalition forces in what he called an 'over-watch' role. The general says that is the plan for the entire country.

He also reports that the new Baghdad security operation is going well so far, with Iraqi commanders taking the promised even-handed approach toward both Sunni and Shi'ite groups that commit violence. But General Odierno also said it will take months to see significant results from the effort, and he urged observers to be patient.