Influential American Senator John Kerry has said that United States will monitor Pakistan's firmness in the crackdown on radical Islamic groups and asked Islamabad [Images] to do more to restore its credibility with India.

There are a lot of 'unfulfilled promises' that were made by Pakistan in the aftermath of the attack on the Indian Parliament in 2001 and Islamabad needs to do more to keep its words, Kerry said. Though the bar is high for Pakistan to re-establish its credibility with India, particularly because of these unfulfilled promises, Kerry urged both countries to resume their stalled peace talks. But he said the US will monitor Pakistan's firmness in the crackdown.

"We are going to watch and hopefully cooperate in the process because we have an interest and we have a case," he said.

Kerry, who has been named as the chairman of the powerful Senate Foreign Relations Committee and is close to President-elect Barack Obama [Images], said Pakistan appeared to be determined to prosecute anyone against whom sufficient evidence of involvement in the Mumbai attacks is available. "The (Pakistani) leadership is very clear that they will prosecute the accused," he said.

The Democrat Senator said this time the Pakistani action would not amount to temporarily closing down camps or making simple house arrests. He said Pakistani leaders had assured him that "they intend to prove their bona fides with respect to this effort."

However, India will not be satisfied merely by words. "It has to be shown some action," Kerry stressed.

He said though the US is committed to giving financial aid to Pakistan, it will not help unless a firm understanding is given about how the government planned to deal with terror groups operating from the country's soil.

Kerry's remarks about the unfulfilled promises, made during an interaction with a small group of journalists on Tuesday night, was an apparent allusion to Islamabad's promise to crackdown on terrorists operating from Pakistani soil, who were linked to the attack on the Parliament.

Though Pakistan banned the Lashker-e-Tayiba in the wake of the Parliament attack, its activists, including its chief Hafiz Mohammed Saeed, continued to operate openly and regrouped by setting up the Jamaat-ud-Dawah.

Kerry also said that India is not aware of all that Pakistan has done to crack down on elements accused of being involved in the attacks in Mumbai. He attributed the current diplomatic standoff between Pakistan and India to 'misunderstanding and miscommunication' between the two countries.

"Not all actions taken by Pakistan are known to India. More people have been detained by the Pakistani authorities than what is known to the Indians," said Kerry, who met President Asif Ali Zardari [Images], Prime Minister Yousuf Raza Gilani [Images], Foreign Minister Shah Mehmood Qureshi and army chief General Ashfaq Parvez Kayani during his visit to Islamabad.

Kerry said he believed Pakistan is sincere in the actions it is taking against groups accused of involvement in the Mumbai attacks.

He said he was optimistic that the crackdown on terror groups would be different this time because Pakistan itself is a victim of terrorism. "It is a very important choice and is also linked to economic realities," he said.

"I have heard condemnation of the incident from all leaders, who have also expressed determination not to allow individual entities like LeT to make foreign policy decisions of the country, or to sidetrack the chosen path of the government and people of the country," he said.

Kerry said Pakistan's civil and military leadership were cognisant of the need for rooting out any group that threatened to detract Pakistan from the democratic path.