'This afternoon, the White House National Security Council convened officials from counterterrorism and intelligence agencies as well as the State and Defense Departments,' the White House said in a statement.
'The US government continues to monitor the situation, including the safety and security of our citizens, and stands ready to assist and support the Indian government.'
Over 100 people died in coordinated attacks at two of Mumbai's top luxury hotels and the main Chhatrapati Shivaji railway station late on Wednesday, officials said.
A group calling itself the 'Deccan Mujahedeen' claimed responsibility.
One British guest of the Taj Mahal hotel told local Indian television that armed men had herded people, including himself, to the hotel's upper floors.
'They said they wanted anyone with British and American passports,' he said.
US president-elect Barack Obama slammed the attacks and said the United States must work to strengthen ties with India and other nations to 'root out and destroy terrorist networks'.
'These coordinated attacks on innocent civilians demonstrate the grave and urgent threat of terrorism,' Obama's chief national security spokesperson, Brooke Anderson, said in a statement.
'The United States must continue to strengthen our partnerships with India and nations around the world to root out and destroy terrorist networks.'
Mr Obama spoke by telephone with Secretary of State Condoleezza Rice for an update on the situation, an official in Obama's transition office said on condition of anonymity.
He then spoke to the US ambassador to India Ranendra Sen, 'and conveyed that his thoughts and prayers' are with the victims, the official said.
The US State Department condemned the attacks as 'horrific,' and said it was monitoring the situation closely.
'We strongly condemn the terrorist attacks,' deputy spokesman Robert Wood said in a statement.
'Our sympathies go out to the families and friends of those killed and injured, and to the people of Mumbai,' he added, saying the department was not aware of any American casualties.
US Secretary of State Condoleezza Rice 'has been briefed on the attacks in Mumbai and is monitoring the situation closely,' another State Department official said, adding that Dr Rice is in contact with officials at the US Embassy in New Delhi and the US consulate in Mumbai.
Dr Rice 'will be reaching to Indian government officials as well,' said the official.
The State Department said it was not aware of any American victims in the series of shooting and bombing incidents apparently targeting foreigners in India's financial capital.
The agency established a call center for Americans concerned about family or friends visiting or living in Mumbai.
New York Mayor Michael Bloomberg joined the calls of condemnation Wednesday and said the bloody attacks were a reminder of 'dark forces' in an increasingly inter-connected world.
'Today a horrific series of attacks in Mumbai, India reminded us that there remain dark forces in the world that think killing innocents is a way to advance an agenda,' Mr Bloomberg said in a statement. -- AFP