New Delhi, July 12 - After having indicated that state actors - meaning Pakistan's notorious Inter-Services Intelligence (ISI) - could have been behind the Mumbai terror attack in November last year, India is now trying to tackle those who masterminded the attack through the very agency that it held responsible for it.

Prime Minister Manmohan Singh said Saturday that the Indian high commissioner in Pakistan, Sharat Sabharwal, had recently met ISI chief Ahmad Shuja Pasha in this regard.

'Our high commissioner (in Pakistan) has recently spoken to the ISI chief and their foreign office. We are hopeful that they will move ahead in punishing those behind the Mumbai terror attack,' the prime minister told media on board Air India One while returning from the G8-G5 summit in Italy's quake-hit town of L'Aquila.

'They have given us some information on what they are doing about the perpetrators of the Mumbai attack. I have not given up hope,' Manmohan Singh said.

Pasha is said to have also met other Indian officials in Islamabad recently.

'This is the first time such a meeting has taken place. The DG, ISI, normally does not meet Indian high commissioner or defence attaches in the Indian mission,' Satish Chandra, India's former envoy to Pakistan, told IANS.

Chandra was, however, sceptical of the seriousness of Pakistan to punish the Mumbai attackers. 'It could be just a trick. It is just to show to India and the international community that Pakistan is serious about punishing the perpetrators of the Mumbai attacks, specially ahead of the Sharm-el-Sheikh meeting,' Chandra, also a former deputy national security adviser, said.

The fact that the prime minister mentioned the meeting of the ISI chief with Indian defence attaches also shows that the government is looking for an excuse to resume dialogue with Pakistan, Chandra said when asked about the significance of the development.

The meeting with the ISI chief and Pakistan's foreign ministry is being seen by some as back-room diplomacy between India and Pakistan as top officials and leaders from both sides prepare to meet in the Egyptian city of Sharm-el-Shiekh this week on the sidelines of the Non-Aligned Movement (NAM) summit.