Transcript for This day in history: Oct. 18, 2007

The day in Pakistan began with a triumphant homecoming for former prime minister Benazir Bhutto who has been in exile a 150000. People turned out to greater. She came home hoping for our share of power there were real concerns for her safety however. And tonight as tens of thousands more surrounded her motorcade into Karachi. Two bombs went off near her vehicle more than a hundred people were killed. Bhutto survived but it raises concerns about Pakistan's stability. So we turn to our senior foreign correspondent Jim shoot up. Bhutto's supporters stood in a stunned silence after the first blast and that when less than a minute later a second explosion tore through the crown. Sending people running in every direction. I was helping an injured man when the second bomb went off an eyewitness said I didn't know what was happening. The blast came so close to the special bulletproof bus caring the former prime minister its shattered the windows. Bhutto herself seen here carried a way is gave to unscathed. But all around here the streets were filled with the wounded and dead. Some fleeing to safety others lay on the ground waving for help. Overwhelmed with the injured Karachi's hospitals declared a state of emergency. This was a bloody end to a triumphant return for Buddha. Hundreds of thousands of turned down to we've heard he boldly says its terrorist would not ruin the country. This is that it had pockets not a fifth of the extremists who have tied the dictatorships it. Several Islamist groups including those tied to al-Qaeda had threatened to kill her. For supporting the US led war on terror. She would allow. US policies to carry out attacks in Pakistani soil against extremists. And trained counts and Barry's assets. At least it is a very sensitive issue. Bhutto left Pakistan eight years ago amid charges she looted more than a billion dollars. She returned today after forging a power sharing deal with president surveys me shareh. He hoped to gain enough votes in parliamentary elections next January to serve once again as prime minister. Bhutto returned today pledging to defeat terrorism tonight it is clear she has much to fight. James you know ABC news London. President Bush of course has staked a major part of his foreign policy on Pakistan and general Musharraf. The administration has said instability in that nation jeopardizes this nation. Our White House correspondent Martha Raddatz joins me tonight Martha this has got to concern the administration. It concerns a very much Charlie and the key word there you said it is instability anything that affects Musharraf affects all of Pakistan and affects the United States they are very concerned about us. I hesitate to raise this but obviously the first question is this looks second assassination attempt who was behind it now I'm sure it's been discussed. Bouchard of general Musharraf let her come back into the country but he has not been effusive in his delight. About her returning any possibility he could have been behind it or. Is it terrorists. Where it's certainly a question I asked most of the people like tech who said it's far too early to tell but no one in official Washington. Believes it was more sharks they said basically. That would be crazy because it would create instability but they say far too soon to tell what was but at this point. They are saying terrorists. And still worried about. Her security still worried that there could be further violence. Oh absolutely Charlie I mean double worry about her all the time they worry about Musharraf all the time you know how many assassination attempts he survived and it will probably be many more. All right Martha Raddatz reporting from Washington tonight thanks.

This transcript has been automatically generated and may not be 100% accurate.