"Perhaps Bhutto should have listened to Musharraf and delayed her return to Pakistan until the volatile security situation was better"
ndur5, Irving, US
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The government's denial came as a bomb reportedly ripped through a bus in the main market of Dera Bugti in Baluchistan province.
"There was a bomb explosion in the main bazaar and seven people were killed and six are wounded," Hazoor Baksh, a local police officer, told the AFP news agency.
No one immediately claimed responsibility for the attack, but the region has seen sporadic violence by ethnic Baluch tribesmen demanding greater political autonomy and a larger share of profits from the province's plentiful natural resources.
There have been fears after Thursday's assassination attempt on Bhutto that further attacks could damage Pakistan's already fractured political landscape.
In an editorial titled "Monster of Extremism,", The News, an independent national newspaper, said on Saturday that the bombings "could further polarise an already charged political atmosphere in the country and bring yet more uncertainty to the country's fledgling democratic system".
Bhutto said on Friday that she had sent Pervez Musharraf, Pakistan's president, the names of three people she accused of involvement in Thursday's blast in Karachi.
"I have shared the names with General Musharraf and one of the people is someone that they are [already] watching," Bhutto told the BBC in an interview. She refused to give their names.
Sources in her Pakistan People's party told AFP news agency they included senior army officials, but would not give further details.
But Azim said: "The trauma of the attack has made them say things which probably in coolness of things they will not repeat.
"People's names have been mentioned and names have been hinted at without giving any reason or without giving any proof of their involvement, and that is unfair."
Musharraf vowed to bring the culprits to justice in a telephone call to Bhutto on Friday.
Azhar Farooqi, Karachi police chief, told the AFP news agency: "Investigations are progressing in the right direction, but once again we will avoid pinpointing anyone or blaming it on a certain set of militants.
"There has been a minor piece of evidence found from the site today but we will not be disclosing it. Police have secured the site of the blast and taken samples."
Several hundred protesters burned tyres in pro-Bhutto neighbourhoods of Karachi on Saturday and pelted passing vehicles with stones for a second day, witnesses said.
"They are expressing their anguish over the attack on their leader and the deaths of so many people," Fayaz Khan, a senior police officer, said. There were no immediate reports of injuries.
Bhutto has pledged to stay in Pakistan to fight general elections scheduled for January, but the attack on her motorcade, the worst suicide bombing in Pakistan's history, has cast doubt over her plans to tour the country to gather support ahead of the polls.
Her bulletproof bus, thronged by supporters, had been moving towards the centre of Karachi for 10 hours when a small explosion was heard near the front of the vehicle. That was quickly followed by a larger blast, destroying two police vans that were escorting it.