The Indian government said on Friday the militant attacks on Mumbai had uncovered lapses in security and Prime Minister Manmohan Singh said the strike originated on a neighbor's soil, a clear reference to Pakistan. The ruling Congress party-led coalition is under renewed criticism from the opposition that it is weak on security after the three-day rampage by 10 Islamist gunmen in India's financial capital last week capped a series of bomb blasts this year. "I would be less than truthful if I said there were no lapses," new Home Minister Palaniappan Chidambaram told reporters in Mumbai. "These are being looked into. We will address the causes that led to the lapses." Chidambaram took the post on Sunday after his predecessor quit amid public fury at the government's failure to prevent the attacks. Elections are due by May and analysts say Singh must demonstrate decisive action to counter criticism over security. Singh, speaking at a media conference, said the territory of a neighboring country has been used for the crime. Pakistan has condemned the assault, denied state involvement and promised to help the Indian probe. But it wants to see proof first. Pakistani Prime Minister Yousaf Raza Gilani said on Friday the Mumbai attackers must not be allowed to derail the peace process between India and Pakistan. He reiterated Islamabad's offer to work with India to find out who was behind the "ghastly acts of terrorism." "We should not allow them to succeed in their nefarious designs," he said in a speech to European ambassadors. Mumbai police have said the gunmen were controlled by the Pakistan-based Lashkar-e-Taiba (LeT) group, blamed for earlier attacks in India. LeT is on U.S. and Indian terrorist lists. There was evidence of some Indian complicity in the attacks, police in the north Indian state of Uttar Pradesh said. In February, police arrested an LeT-linked Indian named Faim Ansari after an attack on a police station. He was carrying maps of Mumbai, Special Task Force chief Brij Lal said. "Ansari, who was later handed over to the Maharashtra police, carried some road maps highlighting several important landmarks of south Mumbai that became the target of last week's terrorist attack," he said. Mumbai Joint Commissioner of Police Rakesh Maria said Ansari was in jail in Uttar Pradesh. India has blamed ISI for using militant groups like LeT in earlier attacks and as proxies in the latter years of their 60-year conflict over the disputed Himalayan region of Kashmir.