The government said on Friday that its interrogation of purported al-Qaida number three, Abu Farraj al-Libbi, was progressing well, although Interior Minister Aftab Khan Sherpao denied a report that authorities had foiled another plot by Muslim fighters on Musharraf's life.
Al-Libbi was arrested on Monday in northwestern Pakistan. He is accused of masterminding two bombings in December 2003 that narrowly missed the military leader. It is hoped he can provide clues to the location of Usama bin Ladin.
Sherpao also said security forces had arrested "seven or eight" suspects on Thursday in the eastern city of Lahore and confiscated weapons.
It was the latest of a series of reports of arrests of terror suspects - mostly unconfirmed by officials.
Information Minister Sheikh Rashid Ahmed said the arrested men included associates of a junior Pakistani air force technician who was convicted and sentenced to death in November for involvement in the 2003 bombings.
"He (al-Libbi) was the mastermind of local terrorists"
Sheikh Rashid Ahmed,
Pakistani information minister
The technician later escaped custody but was recently recaptured.
Asked whether the arrests were linked with al-Libbi's capture, Ahmed said: "He (al-Libbi) was the mastermind of local terrorists."
Police have been on maximum alert outside foreign embassies in Islamabad and elsewhere in Pakistan since al-Libbi's arrest, according to Interior Ministry officials and Mohammed Aslam Ahsan, head of a special security wing in charge of guarding foreign missions.
Meanwhile, Sherpao dismissed as untrue a report that another group allegedly arrested a week or so before al-Libbi had been in the early stages of planning another attack to kill Musharraf.
Abu Farraj al-Libbi is said to be
al-Qaida's number three
"There is not truth in this," Sherpao said.
A Pakistani intelligence official, speaking on condition of anonymity, said on Friday that at least seven suspects - led by a Pakistani who had been freed from prison in Afghanistan - were arrested in late April in the eastern Punjab province.
He said they had confessed to a plot to assassinate Musharraf because of his support of the US-led fight against al-Qaida and the Taliban in Afghanistan - although he said they had not decided when or where to execute the attack.
Pakistan's Prime Minister Shaukat Aziz said on Friday that al-Libbi's interrogation was going well but the location of bin Ladin - long thought to be hiding in the mountains between Pakistan and Afghanistan - remained a mystery.
The suspects reporteldy confessed
to trying to assassinate Musharraf
"We have no idea about bin Ladin, but certainly al-Libbi is a senior member of al-Qaida (that) we were on the lookout for a while," Aziz told reporters during a visit to Malaysia.
"I know the interrogations are going on and they are proceeding well," he said, describing the arrest as a "good development" in the war on terrorism.
An intercept by US agents of a mobile phone call made by al-Libbi reportedly helped Pakistani agents to track him down.
However, Brigadier Javed Iqbal Cheema, head of the Interior Ministry's Crisis Management Cell, denied that US officials were sitting in on the interrogation of al-Libbi, under way at an undisclosed location in Pakistan.
"Our own (intelligence) agencies are investigating him. No one else is involved in it for the time being," Cheema said.