Time Magazine said even the most idealistic internationalists know that the number of nuclear-armed states is likely to "grow rather than shrink in coming years."

The production of dangerous materials is increasing around the globe, it added.

In addition, Time said many countries are still unaware of the severity of the issue, although many others have achieved consensus on it.

"Some countries have been more supportive in spirit than in fact," Time remarked. However,"many countries participating in the summit have concluded that tightening security measures around their nuclear material is not worth the cost and effort," the magazine said, adding that some countries have been skeptical about the extent of the threat posed by nuclear terrorism.

"There's disagreement over how much physical security is needed," David Albright of the Institute for Science and International Security agreed.

What concrete achievements can be produced at the summit remains a question, observers here said.

Obama hopes his goal of securing all vulnerable nuclear materials worldwide within four years will be endorsed by all summit countries at a closing session Tuesday, even if the means to accomplish it are unclear.

"Unfortunately, we have a situation in which there is a lot of loose nuclear material around the world," Obama said Sunday. "And so the central focus of this summit is getting the international community on a path in which we are locking down that nuclear material in a very specific time frame, with a specific work plan."

However, Time on Monday quoted U.S. administration officials as predicting that the gathering will "produce more paper than progress."

"There will be the non-binding communique, wherein the leaders will declare the dangers of nuclear proliferation," it said, adding although "the summit will produce a 'work plan' of steps that individual states will take to secure their nuclear materials, that too will be non-binding."

While acknowledging that President Obama did the right thing in convening a summit and bringing together some 40 heads of state to address the issue of nuclear terrorism, French President Nicolas Sarkozy announced Monday that France will never abandon its nuclear weapons -- a statement that struck a note of discord at the summit.