The IAEA board of governors is studying a 30-page confidential report on Iran's nuclear program that covers the past two decades. The agency's internal document contains a number of damning findings, and raises serious concerns about Iran's breaches of international obligations.

It notes that Iran repeatedly failed to report nuclear material or incorrectly declared it lost. The IAEA says inspectors were denied access to an important site because the Iranians said they could not find the keys. The inspectors saw this as a deliberate ploy to conceal equipment from the agency.

The report also finds that Iran has separated small quantities of plutonium that could be used in bombs without informing the agency. But the IAEA says it is too early to make final conclusions. While the past pattern of concealment casts doubts on Tehran's claim that its nuclear program is purely peaceful, the agency says the evidence of previously undeclared nuclear material and activities does not prove the existence of a nuclear weapons program.

Washington disagrees and criticizes the report for playing down what it sees as obvious evidence of a nuclear weapons program.

A Vienna-based western diplomat said most weapons programs began with what is described in the report as small-scale laboratory work. He said Iran never volunteered information, but has only just begun to respond under international pressure.

IAEA spokesman, Mark Gwozdecky, says his agency is sticking by its report.

"We stand by the report," he said. "However, it is a classified report and will be considered at next week's board of governors meeting. They [the board members] are currently considering the report that we issued on Iran and they will meet on November 20 into 21 to consider a number of items including what, if anything, to do about the situation in Iran and so a formal result from this process should only be expected at that time."