Secretary of State Condoleezza Rice says that Pakistan has a "special responsibility" to cooperate with the investigation into the deadly Mumbai attacks.

Indian and U.S. officials have blamed the three-day assault on militant groups based in Pakistan.

Rice said the United States expects all "responsible governments" to help with the investigation and "Pakistan has a special responsibility to do so and to do so transparently, urgently and fully."

Rice met Wednesday with Foreign Minister Pranab Mukherjee and other senior leaders during a visit to New Delhi.

Last week's attacks against 10 sites in Mumbai killed at least 171 people.

Rice said it was too early to say who was responsible for the attack, but: "Whether there is a direct Al Qaeda hand or not, this is clearly the kind of terror in which Al Qaeda participates," she said during a press conference.

Pakistan's president, meanwhile, said any of the 20 suspects wanted by India would be tried in Pakistan if there is evidence of wrongdoing.

U.S. officials have pointed the finger at Pakistani-based groups in the attacks and have pressured Islamabad to cooperate in the investigation.

Rice delivered U.S. condolences in the Indian capital, but her message at the start of an emergency tour was directed largely at Pakistan.

"This is a time when cooperation of all parties who have any information is really required," Rice said.

Adm. Mike Mullen, chairman of the Joint Chiefs of Staff was in Pakistan on Wednesday.

In Washington a Mullen spokesman said the attacks reflect a growing sophistication among extremist groups. The United States is encouraging a regional approach to security concerns.

U.S. and British citizens were the targets of the violent siege in Mumbai last week, although most of those killed in India's financial capital were from India, Defense Secretary Robert Gates said Tuesday.

Six Americans died.

The same group that carried out last week's attack is believed to be behind the 2006 Mumbai train bombings that killed more than 200, National Intelligence Director Mike McConnell said Tuesday during a speech at Harvard University.

McConnell did not identify the group by name. However, the Indian government has attributed the 2006 attack to Lashkar-e-Taiba, a Pakistani terrorist group based in Kashmir, and the Students Islamic Movement of India.

McConnell is the first U.S. official to publicly identify Lashkar as the likely perpetrator. Earlier Tuesday, a senior State Department official told reporters only that evidence suggests that the brutal, prolonged attack had some roots in Pakistan. Privately, U.S. and foreign counterterrorism officials fingered Lashkar last week.