State Department officials in Washington are acknowledging that the WikiLeaks publication of thousands of classified diplomatic documents is making life more difficult for diplomats, even though U.S. Secretary of State Hillary Clinton has said the release will not interfere in any way with U.S. diplomacy efforts.

State Department Spokesman P.J. Crowley told reporters in Washington Thursday that Secretary Clinton has made a number of phone calls in recent days to express regret for the release of classified State Department cables.

"On Friday she talked to China, Germany, France, the U.K., Afghanistan and Saudi Arabia," said P.J. Crowley. "On Saturday, she talked to Canada. On Sunday, she talked to China again. "

And, Crowley said, in the past week Clinton has met with a number of her counterparts and made other phone calls, most recently to the presidents of Pakistan and Argentina, and a call earlier this week to the president of Liberia.

Clinton departed on a diplomatic trip to the Near East, Central Asia and Bahrain on Monday, the day after the WikiLeaks release began. Speaking in Kazakhstan Wednesday after a day of diplomatic meetings, Clinton said the massive leak would not interfere with diplomatic efforts.

" I have not had any concerns expressed about whether any nation will not continue to work with and discuss matters of importance to us both, going forward," said Hillary Clinton.

But, as Crowley pointed out at the State Department Thursday, officials in foreign capitals are now delving into the documents. Some cables reportedly contain less-than-flattering descriptions of world leaders' personal and professional lives.

"Countries, depending on what they've seen and what they've read, are reacting," he said. "We anticipate that for a period of time, some government officials that have talked to us freely in the past may be more reluctant. "

Crowley said diplomatic outreach is continuing, from high-profile calls placed by the secretary of state down the ranks to the deputy secretary, ambassador and counselor level at embassies around the world.

State Department officials have emphasized that policy is made in Washington and not in the diplomatic messages that are sent from embassies to the U.S. capital. They say the best way to evaluate U.S. policy is to look at U.S. policy and not candid cables.

WikiLeaks continues to release documents in batches, ensuring that the issue will not just blow over. For instance, a classified cable released Wednesday refers to Moscow as a "kleptocracy."

The State Department says it will not comment on what it says are alleged to be State Department cables, but Crowley acknowledged that people are indeed reacting negatively to the content of those messages.

" This is having an effect," admitted P.J. Crowley. "Undersecretary Bill Burns was on the Hill yesterday [Wednesday] and he made clear that this is going to make the conduct of diplomacy for a period of time more difficult. I mean, for human nature reasons, if none other. You know, we're not happy at the release of these documents, and I have no doubt that countries and leaders looking at the documents out of context are not happy, as well. "

Secretary of State Clinton is expected to continue conversations about WikiLeaks when she meets with counterparts in Bahrain.

The head of the United Nations' nuclear agency says he cannot confirm that Iran's atomic activities are peaceful.

Yukiya Amano says Tehran has not been providing the cooperation needed for International Atomic Energy Agency (IAEA) inspectors to clear up questions about its nuclear activities. He commented at the start of an IAEA board meeting Thursday in Austria.

His remarks come ahead of next week's meeting between Iran's top nuclear negotiator, Saeed Jalil, and EU foreign affairs chief Catherine Ashton. Ashton will represent the five permanent U.N. Security Council members and Germany in talks about Iran's nuclear program.

Western nations have accused Iran of pursuing nuclear technology to make weapons. Iran denies the charge.

Amano also told the board he has asked Syria for greater cooperation in an ongoing probe into a suspected nuclear site. He also said he has "great concern" about North Korea's nuclear program.

At the recent NATO summit, the 28-member alliance agreed to end military operations in Afghanistan by 2014 if conditions are right. The leaders also agreed to a new mission statement. But many analysts say the meeting between NATO leaders and Russian President Dmitry Medvedev was the highlight of the Lisbon meeting.

Russia-NATO issues

The meeting between President Medvedev and NATO leaders was held in the context of the Russia-NATO council which brings together the 28 members of the Western alliance plus Russia. It was a parallel meeting to the official NATO summit and provided a venue to discuss issues important to both sides.

Missile defense

One of the key issues discussed was missile defense. The Bush administration proposed to deploy ground-based ballistic missile interceptors in Poland and a radar station in the Czech Republic. The Russians strongly opposed such a plan, saying it was aimed against Moscow, a view rejected by U.S. officials.

Ohio Wesleyan University NATO expert Sean Kay says the Obama administration proposed a more mobile, regional missile-defense system. And that system was approved by the NATO leaders.

"They have agreed in principle to begin the process of building an architecture for ballistic missile defense that would in theory cover all of Europe," Kay said. "I am not sure that's actually technically possible at this stage, but it is a significant victory diplomatically for the Obama administration. It is a major shift from the hard, heavy pressing for ballistic missile defense that the Bush administration pushed through and only got begrudging acceptance of that in the NATO alliance and of course, very much upset the Russians at the same time."

Missile defense cooperation

But in what many analysts say is a major shift, President Dmitry Medvedev has accepted a NATO invitation to cooperate on missile defense. Lowell Schwartz is a NATO and security expert with the RAND Corporation.

"Russia has been firmly in opposition," Schwartz said. "And this has been a major bone of contention, and the fact that Russia and the president (Medvedev) has agreed that Russia will certainly not stand in the way and would like to help and participate, is a very important milestone."

Promising shift

The head of the private research firm, the Arms Control Association, Daryl Kimball, says Moscow's shift is promising.

"But as you heard from the Russian officials, they still have a lot of questions about how this might work," said Kimball. "They want to make it clear that this should not simply be a defense for Western Europe and not European Russia. And there has been talk, we have to remember, for decades about potential cooperation between the United States and Russia on missile defense sharing technology, sharing early-warning radars, but that cooperation is going to be much more difficult to achieve when you get down to brass tacks and we will have to see how this develops."

On Afghanistan, Russia has agreed to facilitate and expand railway transit of non-lethal supplies from Europe to that country.

Daryl Kimball says this is part of the Obama administration's efforts to reset relations with Moscow.

"Russia's cooperation mainly has to do with helping NATO with its supply lines going into Afghanistan," Kimball added. "It means the United States does not have to depend solely on supply lines through Pakistan which is very important for NATO, gives it greater flexibility. And so I think that is another sign that the Obama administration approach with Russia is paying dividends in terms of tangible Russian cooperation on issues that matter to the United States and NATO."

But Sean Kay says Russia helping NATO in Afghanistan can be a double-edged sword.

"Because at the same time they can signal support for access to corridors, they are also sending the message that we also have the power to shut that down if things do not go our way," Kay said.

Support for START

Analysts say NATO leaders also provided a boost to President Barack Obama when they expressed support for the Strategic Arms Reduction Treaty between Washington and Moscow. The U.S. Senate is supposed to vote on whether to ratify the treaty, but the timeframe is uncertain.