A previously unknown Muslim group called Deccan Mujahideen – a name suggesting origins inside India - has claimed responsibility for the attacks. But Indian officials said the lone surviving gunman, now in custody, told authorities he belonged to a Pakistani militant group with links to the divided Himalayan territory of Kashmir.

India has blamed "elements" from Pakistan for the 60-hour siege during which suspected Muslim militants hit 10 sites across Mumbai.

Pakistan denied it was involved and demanded evidence.

India has repeatedly accused Pakistan of complicity in terrorist attacks on its soil, many of which it traces to militant groups fighting Indian rule in Kashmir. The U.S. has tried to persuade Pakistan to shift its security focus from India, with which it has fought three wars, to Islamic militants along the Afghan border.

Rice said Pakistan's U.S-backed civilian president, Asif Ali Zardari, has pledged to improve relations.

Zardari replaced President Pervez Musharraf earlier this year and has established polite but distanced relations with Washington. Musharraf was a military man and a Bush administration ally against terrorism, but that closeness cost him support at home.

"It's a difficult task for this new Pakistani government," Rice said, referring to the way Islamabad will respond to the attacks next door. "They know this is a time to step up to the task."

Rice spoke Sunday with President-elect Barack Obama, their third conversation about India in as many days.