Pentagon officials say they are keeping a close eye on Iraq and its weapons development efforts, even as the main focus of U.S. military activities remains Afghanistan. Defense officials have little faith in the ability of United Nations inspectors to do the monitoring job.

Pentagon officials do not appear to be holding out much hope for possible upcoming talks between U.N. and Iraqi officials about the return of U.N. arms inspectors to Iraqi territory.

The United Nations wants the inspectors to return after an absence of several years, to determine whether authorities in Baghdad are trying to develop or acquire weapons of mass destruction - chemical, biological and nuclear weapons.

U.S. officials said there is no doubt of Iraq's interest in attaining such an arsenal. But they make clear they do doubt the ability of U.N. inspectors to find solid evidence.

The clearest expression of that doubt came this past week from Defense Secretary Donald Rumsfeld. He told reporters the experience of international inspectors who worked in Iraq after the Gulf War showed they were relatively ineffective.

"There were inspectors in that country for a long time, and they did a lot of looking around and they found some things. But for the most part, anything they found was a result of having been cued to something as a result of a defector giving them a heads up that they ought to do this, that or the other thing," Mr. Rumsfeld said.

Mr. Rumsfeld said the lengthy absence of inspectors, the lack of success of the original monitors and Iraq's development of better methods for hiding its weapons all means any renewed inspection program will have to be very rigorous.

He does not think that is likely.

"It would have to be an enormously intrusive inspection regime for anyone - any reasonable person to have confidence that it could in fact find, locate and identify the government of Iraq's very aggressive weapons of mass destruction program, which has been going on for years," Mr. Rumsfeld said.

He said Iraqi leader Saddam Hussein has definitely been trying to develop a nuclear capability and - in his words - is working to enhance his biological and chemical weapons.

And that has U.S. military officials worried. One of their main concerns is the fact that Iraqi troops have in the past used chemical weapons - against Iranian forces during the Iran-Iraq war and also against ethnic Kurds in Iraq itself.

Pentagon officials refuse to said whether they are considering any military options for removing the threat of Iraqi weapons of mass destruction.

For the moment, senior officials stress the need for continued diplomatic pressure - including the continuation of economic and other sanctions against the Baghdad government.

Still, in the long run, defense sources insist there needs to be a leadership change in Iraq. Saddam Hussein, they say, must go. They say it is the only option.

The only problem, these defense sources have said, involves who would replace him. For the moment, they say, the options do not look good.

Still, the Defense Department has provided limited military training to about 130 members of the Iraqi opposition.

But the training has been in such areas as medical care, logistics and the like - not lethal combat or weapons training.