New Delhi: A week after the killing of al Qaeda chief Osama bin Laden, Prime Minister Manmohan Singh on Monday night spoke to US President Barack Obama over phone and discussed the situation in the region.

Sources, however, did not divulge whether the two leaders discussed the bin Laden issue.

A PMO spokesman said Singh and Obama discussed further development of Indo-US relations and the situation in the region.

"It was a warm conversation which covered wide-ranging subjects", he said.

This is the first conversation between the two leaders since the killing of Osama on May 2 in a raid by US Special Forces in the garrison city of Abbotabad.

Singh had termed bin Laden's killing as a significant step forward and asked the international community and Pakistan in particular to work comprehensively to end the activities of all terror groups.

The Prime Minister had hoped that bin Laden's elimination would deal a "decisive blow" to al Qaeda and other terrorist groups".

The telephonic talks came on a day when the US President raised questions about the possibility that "some people inside the government" in Pakistan may have been involved in providing support structure for the slain terrorist.

"We don't know whether there might have been some people inside of government, people outside of government, and that's something that we have to investigate and more importantly, the Pakistani government has to investigate," he told the 'CBS News' in his first interview after bin Laden's
death.

"We think that there had to be some sort of support network for bin Laden inside Pakistan. But we don't know who or what that support network was," Obama said.

In Islamabad, Pakistan Prime Minister Yousuf Raza Gilani virtually questioned the US role in the 1990s that gave birth to Taliban and al Qaeda saying Pakistan alone cannot be blamed for bin Laden even as he dismissed criticism of Islamabad's complicity in sheltering him.

Agencies