MUMBAI (AFP) - The well-coordinated bomb attacks on Mumbai rail network that left 183 dead bore the hallmarks of Islamic militant group Lashkar-e-Taiba, a senior officer said. Police, however, said they were awaiting test results from evidence at the scene of the blasts including several commonly-used timing devices believed to have set off the seven blasts within about 10 minutes. Police had known for a "few months" that Mumbai was a target after a series of raids on suspected Islamic militants netted explosives and weaponry in Maharashtra state of which Mumbai is the capital, said state police chief P.S Pasricha. "The modus operandi appears to be similar to Lashkar-e-Taiba," Pasricha told reporters on Wednesday. "I cannot categorically say that it was them as those (forensic) reports have yet to come in." The anti-terrorism force has taken over the inquiry and visited addresses across the city Wednesday but had not yet arrested anyone, a senior officer told AFP. The wreckage of the six first-class carriages was taken to a railway shed where bomb squad officers searched for clues, according to a railway official. A seventh blast was in a subway at a station. "It seems pencil timers were used to carry out the blasts one after the other," a top official from Maharashtra`s home department told AFP. Mumbai is the state capital. "We have collected some vital clues in this regard and the Central Forensic Laboratory has been requested to examine them without any delay," he added, on condition of anonymity. Police said high-grade explosive was used in the blasts during the evening rush hour Tuesday. Tests were being carried out but officers suspected the use of RDX or plastic explosives because of the power of the blasts. Officials said they had not yet identified any group behind the outrage but Pasricha did not rule out smaller regional groups operating in concert with a bigger oufit. Newspaper reports claimed police were investigating growing ties between Lashkar-e-Taiba (Army of the Pious), and the Students Islamic Movement of India (SIMI). Lashkar-e-Taiba, a militant group fighting Indian rule in disputed Kashmir, denied it was behind Tuesday`s bombings, the worst in India since a series of blast in Mumbai in 1993 left more than 250 dead. The Pakistan-based outfit has been banned by both New Delhi and Islamabad and declared a terrorist organistion by the United States. SIMI, a students` outfit, was banned in India in 2001. The Hindu newspaper, quoting "highly placed government sources", said the bombings were "clearly a job of Lashkar" and designed to raise "the tempo of communal violence". No group has yet come forward to claim responsibility. The head of the anti-terrorist squad said a "big power" was behind the operation that also injured more than 700. "It was a well-coordinated and well-planned operation and it seems some big power is behind all this," the police anti-terrorism squad chief K.P. Raghuvanshi told Headlines Today television channel. He did not elaborate. Maharashra deputy chief minister R.R. Patil told reporters late Tuesday that the blasts represented an intelligence failure. "It`s not just the state intelligence department and the elite anti-terrorist squad that failed. Even the intelligence bureau at the Centre (federal government) had no inkling of the blasts," Patil was quoted as saying in the Times of India. Senior Mumbai police officer Arup Patnaik said officers were out on the streets Tuesday night but there was no sign of increased communal tensions in the city, which has a Muslim minority.