"We would also expect that the government of Pakistan take credible steps to dismantle the infrastructure of terrorism in Pakistan."
India has in the past consistently accused Pakistan of not doing enough to arrest those responsible for the Mumbai attack.
Pakistan has registered a criminal case against six men held in custody and two others still at large, Rehman Malik, the country's interior ministry chief, said.
"Some part of the conspiracy has taken place in Pakistan and ... according to the available information, most of [the conspirators] are in our custody," Malik said at a news conference in Islamabad.
He said a "first information report", which clears the way for a police investigation, had been lodged against the eight suspects on charges of "abetting, conspiracy and facilitation'' of a terrorist act.
Malik said that police had traced to Pakistan a boat engine used by the attackers, and infiltrated two hideouts of the suspected attackers in the country.
Al Jazeera's correspondent Kamal Hyder said Pakistan has put 30 questions about the raid to India and asked for DNA samples of Mohammad Ajmal Kasab, the sole Mumbai attack suspect caught alive by Indian officials.
"They want Kasab to be brought to Pakistan for a trial, although there is no extradition treaty between the two countries," he said.
Ravi Sawnhey, a security analyst and former director-general of India's military intelligence, said that Pakistan's admission should have come earlier.
"It has come after a lot of pressure from the international community. I would suspect that Pakistan has done this to prepare for the visit of [Richard Holbrooke] the US special representative [to Pakistan and Afghanistan]," he told Al Jazeera.
"In any case, it is a positive development and hopefully this will be followed up by sincere action."
India has blamed the Mumbai attacks on Lashkar-e-Taiba, a group which says it is fighting against New Delhi's rule over Indian Kashmir.
Islamabad has been under pressure from India and major world powers to crack down on the Lashkar, which Pervez Musharraf, the former president of Pakistan, banned in January 2002.
New Delhi says all 10 armed men involved in the Mumbai attack were Pakistanis.
It also says that the men's handlers in Pakistan had kept up communication by phone during the three-day assault on luxury hotels, a railway station and a Jewish community centre.
Prem Shankar Jha, a former adviser to the Indian prime minister, said that the Indian government has promised it will aid Islamabad's investigation into the Mumbai attacks by giving all the information it has on the incident.
"A certain level of confidence has been built up," he told Al Jazeera.
"Don't forget that [at one point] India was [not keen] to even hand over the dossier. Only 13 pages of the dossier were given to Pakistan directly, the rest of the evidence went through the Americans and the British.
"That showed not only a high level of anger [on India's part] but a high level of mistrust. That stage has now passed."