President Bush (search) made an unexpected visit to the Russian Embassy on Sunday where he signed a book of condolences for victims of the school hostage seizure and expressed outrage at the actions of "evil terrorists."

"The atrocities that took place in the school were beyond comprehension," the president told reporters after writing a one-page note in the book.

"Many in America and, I know, many Russians cannot conceive the heart of a person who could mow down innocent children. The killers once again remind us of the duties we have as free people to work in concert, to work in unity, to make this world a better place," Bush said.

Bush said the United States stands "shoulder-to-shoulder" with Russia (search) in the war on terrorism, a central theme of Bush's re-election campaign. That sentiment was echoed in Moscow where Russian defense minister Sergei Ivanov (search) said Sunday that Russia reserves the right to carry out pre-emptive strikes on militant bases abroad.

The defense minister did not say what countries might be possible targets for a strike. Russian officials in the past have said Chechen separatists (search) have bases in nearby Georgia. Also, Moscow has had friction with that country's pro-U.S. government over the issue.

The hostage-taking in the southern Russian town of Beslan (search) ended Sept. 3 in a frenzy of shooting and explosions and the deaths of at least 330 people. On Saturday, the Interfax news agency cited the Russian health ministry as saying 353 people wounded in the hostage-taking remained hospitalized, including 216 children.

Russia's foreign minister said Friday that Chechen rebel warlord Shamil Basayev (search) directed the hostage-taking raid and that Arab militants participated. Basayev has carried out a number of dramatic and bloody hostage-takings in the past in his campaign to drive Russian forces out of the restive republic of Chechnya (search).

Bush flew by helicopter from the presidential retreat at Camp David, Md., landing at the vice president's residence and making a short drive to the Russian Embassy. The stop had not been listed on the president's official schedule for Sunday.

He was greeted by embassy officials in the foyer, where he then wrote his message. First lady Laura Bush signed her name beneath the president's. The contents of his note were not immediately known.

"I'm here to express my country's heartfelt sympathies for the victims and the families who suffered at the hands of the evil terrorists," the president told reporters.