ISLAMABAD - The United States and India have demanded of Pakistan to act strongly against the terrorists involved in Mumbai attacks and warned that in case of non-compliance, Washington and New Delhi would themselves take action against the alleged culprits. "The Indian authorities have sent two letters to Pakistani leadership in the wake of Mumbai carnage and in one letter they blamed Islamabad for the ghastly act of terror while in other they alleged Pakistan based militant organizations, Lashkar-e-Taiba and Jamaatud Dawa for involvement in horrendous attacks," said a diplomatic source while asking for anonymity because of sensitive subject. He said that in the second letter, the Indian officials had also demanded of Pakistan to hand over Dawood Ibrahim, Chota Rajan and Maulana Masood Azhar to India. The message from Washington and New Delhi, according to source, was very clear that those two nations would resort to an action on their own against Pakistan based Jihadi organization if the demands that they had come up with were not accepted. Moreover, the Indians, he said, had also raised fingers towards some militant organizations based in FATA while asking for equally strong action against them. The source said Pakistani authorities were in the process of preparing response to the letters sent by New Delhi adding that hectic consultations were underway in Pakistani capital for the purpose and the reply would be made after the return of President Asif Ali Zardari to Pakistan, who is currently in Turkey to attend trilateral summit involving Pakistan, Afghanistan and Turkey. He said that the Pakistan Government could go for a crackdown on the militant organizations in the face of mounting pressure by the western capitals and especially Washington. Another diplomatic source when contacted said that the US Secretary of State, Condoleezza Rice, who recently visited Islamabad to discuss the Mumbai carnage, asked Pakistan that it must cooperate fully with India as the evidence provided by New Delhi to Washington was more than sufficient. He said that Secretary Rice had thrown the ball in the court of Pakistan and the US authorities were waiting for a response from Islamabad. "If Islamabad decided not to deliver on US and Indian demand, then the Americans would decide what to do next. As for now we know one thing that Delhi and Washington are one on Mumbai attacks and the guns are directed towards Pakistan," he said. The source said that to many any strict action like India going to all out war against Pakistan or increase in drone attacks and surgical strikes on Pakistani soil was not even the remote possibility given Islamabad's key role in US-led war on terror. However, he said that war or increased drone attacks were not the only options left with Washington or with India and some other steps could also be taken such as suspension of financial aid to Pakistan that was facing the worst economic crisis in its well over 60 years history. "The other extreme step that could be taken against Pakistan was of declaring it as a terrorism sponsoring state, something that would be disastrous in consequences," the source said. Nonetheless, Pakistan was highly active on diplomatic front to avert such looming scenarios and resolve the threatening crisis with India in an amicable manner.