The deadly Baghdad bombings represent an obvious lapse in security, the U.S. commander in charge of training Iraqi security forces said Thursday, adding that he is personally frustrated with the pace of needed advanced training there.

Army Lt. Gen. Frank Helmick told a Pentagon news conference that he is not certain he can complete some of the high-tech training — including for Iraq's Air Force — by the time U.S. troops are scheduled to leave at the end of 2011.

"What I am personally frustrated with is that ... we must continue to develop the capability inside the Iraqi military," said Helmick. "We are doing that as fast as we can. My frustration is we, I, am not doing it fast enough."

He said he does not know who was responsible for Wednesday's coordinated bombings inside Baghdad's heavily fortified Green Zone, which killed about 100 and wounded 500. Iraqi Prime Minister Nouri al-Maliki is blaming Sunni insurgents.

The successful, nearly simultaneous attacks raised questions anew about the ability of Iraqi security forces to maintain order, and underscored doubts about the government's plan to begin reopening streets and removing blast walls along major city roads.

Helmick did not respond to the question of whether Wednesday's bombing was more a case of mistakes and ineffectual Iraqi efforts as opposed to one involving official collusion with or infiltration by insurgents. Maj. Gen. Qassim al-Moussawi, the chief Iraqi military spokesman in Baghdad, said 11 police and army commanders overseeing security, traffic and intelligence services in the targeted areas have been detained on suspicion of negligence.

Helmick said the U.S. trainers have done the less difficult things — building infantry and police units — but that the bigger challenges of developing forensic teams, logistics capabilities, and the ability to collect and analyze intelligence data, are coming much more slowly.

"The easy part of all that is complete. We're getting to a very technical, costly part of that now," he said. "It's easy to build an infantrymen and an infantry unit. It's very very difficult and it takes time to build an intelligence, surveillance and reconnaissance technician."

Part of the problem, he said, is that progress depends in part on the Iraqi government's willingness to buy ships and other needed equipment. For example, he said the Iraqis only recently approved the purchase of patrol boats, needed to protect oil platforms off the coast.

Helmick said the boats will take a year to build, triggering concerns that the U.S. may not be able to train the crews by the end of 2011.

The Iraqis have made strides in intelligence gathering, Helmick said, noting that their air force has the aircraft needed and pilots and technicians are being trained to provide intelligence to forces on the ground.

"I do not want to overstate their capability," said Helmick. "It is a very, very limited, basic capability now, where they are flying sorties and providing live downlinks to mobile stations" on the ground.

Helmick said Wednesday's carnage showed Iraqis will need to remain ever-vigilant.

"These events clearly demonstrate that security is not only an ongoing process, it really is a never-ending commitment," he said.

"The Iraqi security forces have demonstrated their increased capability and the declining number of attacks over time is proof of that," Helmick said, adding "Yes, we have much work to be done."