India today made its clearest accusation that elements inside the Pakistani Government were behind the Mumbai terror atrocities.

Manmohan Singh, the Indian Prime Minister, said that investigations into the attacks on India's financial capital, which left more than 170 people dead, showed that the ten gunmen who carried out the raid must have had some sort of support from the Pakistani state. "There is enough evidence to show that, given the sophistication and military precision of the attack it must have had the support of some official agencies in Pakistan," he said in a press conference.

He also accused Islamabad of using terrorism as an "instrument of state policy" and said Pakistan had in the past also "encouraged and given sanctuary" to militants hostile to India.

The comments pointed a finger at Pakistan's powerful spy agency, Inter-Services Intelligence, which is known to have fostered militant groups for decades to fight as proxy forces in Kashmir and Afghanistan.

India is convinced that Lashkar-e-Taiba (LeT), a terrorist faction that was founded with the help of the ISI, carried out the Mumbai attacks in November.

Mr Singh's Government dramatically ramped up its diplomatic offensive against Pakistan yesterday, releasing evidence linking "elements" in the neighbouring nuclear-armed state to the Mumbai terror attacks for the first time.

A dossier handed to Pakistan's high commission in Delhi included interceptions of telephone calls made between the ten Mumbai gunmen and their alleged handlers in Pakistan during the attacks. "The commanders in Pakistan are following events on television and are issuing real-time instructions; telling the gunmen to target certain nationalities and religions; to maximise casualties; not to touch Muslims. This is hands-on direction," a senior Indian government official told The Times.

The commands included the order to execute six foreign Jews held at Nariman House, an orthodox Jewish outreach centre, during the Mumbai atrocities, which claimed more than 170 lives in all.

Those giving the orders are alleged to be senior members of LeT. They include Zarar Shah, the LeT's communications chief, who has been arrested in Pakistan and is believed to have admitted his role to Pakistani investigators. "He played a major part," Rakesh Maria, the officer in charge of the police investigation in Mumbai, said.

The dossier, which has also been passed to diplomats from countries including the UK and US, also includes an alleged confession from Mohammed Ajmal Kasab, the sole Mumbai gunman to be captured alive. He says he is a Pakistani national who was trained for more than a year by the LeT in Pakistan. Details of the terrorists' weapons, GPS navigation systems and satellite and mobile phones are also included.

India expects the dossier to increase international pressure on Pakistan to dismantle the support network used by Islamist militants within its borders, much of which dates back to the CIA's backing of Pakistan-based jihadists against the Soviet Union in Afghanistan during the Cold War.

India is also demanding that Pakistan hand over several terror suspects linked to the Mumbai attacks. However, Islamabad has already said it would not comply to such a request and may settle for access being given to them by the FBI, which helped compile key parts of the Indian dossier.

However, the file is unlikely to contain much that Pakistan's security services are not already aware of, analysts said. Ajit Doval, a former director of India's Intelligence Bureau, said: "It will not carry anything spectacular; more likely it will contain refinements of information already widely known. In any case, Pakistan already has more than enough evidence to act upon if they are willing."

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