World leaders were quick to join British Prime Minister Tony Blair in condemning the attacks that claimed the lives of dozens of commuters during the morning rush hour in London Thursday.

In a joint statement issued just hours after the blasts brought that city's massive public transport system to a grinding halt, leaders gathered for the Group of Eight nations summit vowed not to let the perpetrators claim victory.

"We shall prevail and they shall not," Blair said, reading the joint statement to reporters at the exclusive Scottish golf resort, Gleneagles.

It was easily approved by leaders from the G-8 countries -- Britain, Canada, France, Germany, Italy, Japan, the United States and Russia -- as well as the leaders from Brazil, China, India, Mexico and South Africa who are also attending the three-day get-together.

"We are united in our resolve to confront and defeat this terrorism that is not an attack on one nation but on all nations and on civilized people everywhere," said the joint statement also signed by the heads of the United Nations, the International Monetary Fund, the World Trade Organization and the World Bank.

With the summit site protected by an unprecedented security cordon, Blair said G-8 leaders would not allow their annual meetings to be derailed.

They did, however, later concede that a pair of key declarations scheduled Thursday -- on climate change and the world economy -- would have to be postponed for at least 24 hours.

The delay was necessary after the deadly attacks forced leaders to divert their attention from the official summit agenda.

While the other leaders attended individual briefings and addressed the security fallout in their own countries, Blair left Gleneagles for the day, to head to London.

Back in Scotland, U.S. President George Bush told reporters he sent a "message of solidarity" with the British prime minister.

"The war on terror goes on," Bush added.

In his own statement to reporters soon after news of the attacks reached the summit venue, Prime Minister Paul Martin conveyed his condolences to victims.

"We pray for those who have lost their lives, and for their families," he said.

Condemning the series of apparently coordinated explosions as "perfidious attacks," German Chancellor Gerhard Schroeder said the fight against terror must employ "all the means at our disposal."

French President Jacques Chirac called the attacks "indescribable," as he expressed his renewed resolve to fight terrorists' "scorn for human life."

Russian President Vladimir Putin also blasted that attacks as evidence, "we are doing too little to unite our efforts in the most effective way in the battle against terrorism."

"The response to these inhumane crimes wherever they take place -- be it London, New York, Moscow or other countries -- should be absolute condemnation," Putin told reporters.

Recalling the March, 2004 attacks that left 191 rail commuters dead in Madrid, Spanish Prime Minister Jose Luis Zapatero expressed his nation's heart-felt sympathies.

"We, the Spanish people, well understand the suffering that today the British people are undergoing. We share their pain intensely."

In his comments, Mexican President Vicente Fox predicted the attacks could serve to strengthen the resolve of those nations waging the war on terror.

"We not only regret, but we condemn, really condemn, this event," he said. "No doubt that they drove cohesiveness to the thirteen nations that work together this morning."

There was quick evidence that cohesiveness extended beyond the bounds of the G-8 Thursday, as the United Nations Security Council unanimously passed a hastily-drafted resolution condemning the morning explosions.

According to UN Secretary-General Kofi Annan, it is vital G-8 leaders press ahead with their discussions.

"Let us not allow the violence perpetrated by a few to deflect us from addressing the aspirations of billions of our fellow men and women who are demanding change," he said.

In other reaction to the deadly attacks:

_"No cause can justify the killing of civilians,'' Algerian UN Ambassador Abdallah Baali said. "It's obvious that these people want to distract the attention of the international community from the real problems and we can only reject such acts.''

_European Commission President Jose Manuel Barroso called the attacks both "criminal" and "absurd."

"This criminal act [is] not only against Britain, against the British people but against all civilised people in the world that do not tolerate these kind of crimes," he said.

_In a telegram sent on behalf of Pope Benedict XVI, the pontiff offered prayers for those now in mourning.

"While he deplores these barbaric acts against humanity," the telegram read, "he asks you to convey to the families of the injured his spiritual closeness at this time of grief."