The country's Information Minister Shaikh Rashid Ahmad said on Saturday investigations were in the final stages. He, however, refused to specify how many suspects had been arrested so far.
"We have reached their entire network and almost the whole case is in its final stage," the minister said.
Ahmad also said the suspects in all probability had outside links.
"It is not possible that they did not have links to people outside the country. This is what we are working on. Who were their masterminds?" he asked.
Musharraf survived two assassination attempts in the space of two weeks. The first was made by blowing up a bridge his motorcade had used moments before, and the second involved two cars loaded with explosives ramming into his motorcade.
A close ally of the United States in its "war against terror," Musharraf has earned the wrath of Islamic hardliners who have accused him of selling out to the Americans.