Islamabad - The terrorist attacks in Mumbai have strained the improving relations between India and Pakistan, the two South Asian nuclear-armed states.

Indian Foreign Minister Pranab Mukherjee bluntly pointed the finger at Pakistan for being the origin of the well coordinated gun and bomb strikes that have so far left some 125 people dead and over 300 injured, as the commandoes continue to fight to flush out suspected Islamist militants holed up in two Mumbai hotels with hostages, including Israeli nationals.

"According to preliminary information, some elements in Pakistan are responsible," Indian news wire Press Trust of India (PTI) cited him as saying.

The attacks came as the two archrivals - Pakistan and India, which have fought three wars during the 61 years of their existence and came to the verge of fourth in 2002, seemed to be on relatively good terms with each other.

Pakistani President Asif Ali Zardari said last week that "there is a little bit of Indian in every Pakistani and a little bit of Pakistani in every Indian," while unveiling a proposal to commit his nation to a "no first use nuclear weapon policy" during an address to a conference in New Delhi via videolink.

The two countries launched a composite peace dialogue in 2004 to resolve their differences over the disputed Himalayan region of Kashmir and other issues, and introduced several Confidence Building Measures (CBMs), including opening of several roads, railway links and enhancing mutual trade.

The United States, especially the incoming government of president-elect Barack Obama, was counting on the success of peace process to make Pakistan divert its attention from Kashmir, where it has supported Islamist separatists, to the fight against Taliban and al-Qaeda fighters launching cross-border attacks on international forces in Afghanistan.

But the lethal attacks in Mumbai and the following deficit in trust between India and Pakistan might hamper such efforts to increase regional cooperation to beat the terrorists.

Mukherjee refused to make public the evidence that supposedly substantiated the accusations, while the terrorists linked themselves to a previously little known Deccan Mujahidin group based in India.

But another unnamed government official told PTI that three militants were captured from Taj Hotel, one of the scenes of the carnage in Indian financial capital, belonged to Pakistan-based militant group, Lashkar-e-Toiba (LeT).

The LeT, which is waging an armed struggle for independence of India-administered Kashmir, is believed to have close links with Pakistan's military intelligence Inter-Services Intelligence (ISI), at least in the past, as well as with al-Qaeda.

Pakistan officially denies such links and insists that it provides only moral support to the Kashmiri population in what it calls its freedom struggle against Indian occupation of the valley.

"In case there is clear evidence that hawks within Pakistan are involved or any of the agencies are involved, relations will be back to the years of great tension and violence between the two countries," said Ayesha Siddiqa, an Islamabad-based political and defence analyst.

But there were some positive signs from Pakistan.

The leadership of the Islamic state decided to dispatch ISI chief Lieutenant General Ahmed Shuja Pasha to New Delhi when Indian Prime Minister Manmohan Singh made a formal request during a telephone conversation with his Pakistani counterpart Yousaf Raza Gilani on Friday.

"Pakistan has nothing to do with this incident. Pakistan has no link with this attack. We have nothing to hide," Gilnai told reporters.

The Indian authorities want to share proofs of involvement of Pakistan-based militant groups.

"It's a positive move. It will be for the first time perhaps when they (India) will be showing some evidence to the ISI chief, if there is any, and this is an opportunity where we can assure them of our cooperation," said Siddiqa.

President Asif Ali Zardari blamed "non-state actors" for the Mumbai carnage in a separate phone call to Singh, saying they "wanted to force upon the governments their own agenda but they must not be allowed to succeed,"

But he called upon the Indian premier not to "fall into the trap of the militants."

Siddiqa hoped that the move made by Zardari and his team would avert the sort of tensions stirred by militant attacks on Indian parliament in 2001 that pushed the nuclear-armed countries to the brink of war a year later.

"Militancy is a problem which affects both countries and this is not a time for point scoring but a time of sitting down together and saying that this is a problem which we will resolve together," Siddiqa said.