Authorities in Bombay, India are rounding up potential suspects and searching for evidence that could point to who carried out this week's devastating train bombings.
The death toll from Tuesday's explosions is now at least 200, with 700 people injured. Police in Bombay detained more than 200 people for questioning Thursday, but they say no one has been charged or formally arrested.
A man claiming to represent al-Qaida called a news agency based in Indian Kashmir to say that the terror network had set up a wing there. He praised the blasts in Bombay, saying they were triggered by India's oppression of minorities and Muslims.
The Indian army says it is evaluating the claim.
Earlier, authorities said they were looking into a possible link between the bombings and Lashkar-e-Toiba, an outlawed Kashmiri militant group based in Pakistan. Police say the pattern of bombings and the equipment used point to the group.
But it has denied it was involved. Pakistan's Foreign Minister Khursheed Kasuri says it is not fair to automatically blame his country for the bomb blasts in India. He says his country too often is unfairly blamed for such attacks.
President Bush telephoned Indian Prime Minister Manmohan Singh to express sympathy and offer U.S. support to India in its war against terrorism.
At least seven bombs exploded on packed commuter trains during the evening rush hour Tuesday in and near Bombay - India's largest city and financial capital (in Maharashtra state).
Prime Minister Singh says his government will do whatever is necessary to deal with the challenges ahead, and he has called on India's more than one billion people to take a united stand against violence.
In New York Wednesday, United Nations Security Council members issued a joint statement condemning the train bombings and calling on nations to bring those responsible to justice.