WASHINGTON — American military commanders are talking with Iraqi insurgents about cease-fires and other arrangements to try to stop the violence, the no. 2 American commander said yesterday.

And he suggested he might not be able to strictly meet the September deadline for telling Congress whether President Bush’s military build up in Iraq is working.

Lieutenant General Raymond Odierno said commanders at all levels are being empowered to reach out for talks with militants, tribes, religious leaders, and others in the country that has been gripped by violence on a range of fronts including insurgents, sectarian rivals, and common criminals.

“It’s just beginning, so we have a lot of work to do in this,” he said. “But we have restructured ourselves … to work this issue.”

He said he thinks 80% of Iraqis — including Sunni insurgents and Shiite militants — can reach reconciliation with each other, though most Al Qaeda operatives won’t.

“We are talking about cease-fires, and maybe signing some things that say they won’t conduct operations against the government of Iraq or against coalition forces.,” General Odierno told Pentagon reporters in a video conference from Baghdad.

On the assessment of operations that is due in September, he said he thinks it will take longer to tell whether the increase of nearly 30,000 troops will work as intended — that is, to quell violence enough to give Iraqi officials breathing space to work on reconciliation and development issues.

“The way I understand it, is we’re going to be required to provide an assessment in September. So I will provide my assessment,” General Odierno said, adding it might not be complete.

He said he will be able to assess the work of forces that arrived for the beginning of the build up in February, but that the ones just arrived this week won’t be in place for a couple of weeks — meaning it will be August before he might be able to tell how they’re doing.