"The United States stands with the people and the government of India and condemns in the strongest terms these atrocities, which were committed against innocent people as they went about their daily lives," Bush said in a written statement issued Tuesday evening while he was traveling in Wisconsin.
"Such acts only strengthen the resolve of the international community to stand united against terrorism and to declare unequivocally that there is no justification for the vicious murder of innocent people," he said.
Earlier, while at an Allen-Edmonds Shoe Corp. factory in Port Washington, Wis., Bush had declined to react in person to the bombs. "No comments today, thank you very much," he told reporters who asked about the attacks.
In Washington, Secretary of State Condoleezza Rice said she had no information on who was responsible. Other officials said radical Islamic groups may be to blame.
"Let me just say that we condemn thoroughly this terrible terrorist incident," Rice said during a photo session with the Serbian prime minister.
She added, "This kind of hideous incident can happen anywhere in the world against innocent people."
Earlier, State Department spokesman Sean McCormack said the United States would provide help should Indian authorities request it.
India's ambassador to the United States, Ronen Sen, said officials' top priority was to attend to hundreds of injured and to contact relatives of victims. Officials also were investigating details of the blasts, Sen said.
"We have, unfortunately, faced these kinds of situations in the past," he said in an interview with The Associated Press, referring to similar serial blasts in 1993 with targets that included the Bombay Stock Exchange, which killed more than 250 people, and other attacks.
"Our people are resilient," he said. "It's not going to affect our economy."
Two U.S. officials said the attacks matched the methods previously used by Islamic extremist groups that have been active in India during the past several years: Lashkar-e-Tayyaba, or Army of the Righteous, and Jaish-e-Mohammad, or Army of Mohammed.
Sen said that while it was too early to say who was responsible, "the pattern is similar" to past operations by those groups.