Days before militants struck Mumbai, Indian authorities were warned of an imminent attack by Islamist gunmen who would arrive by sea, according to a senior coast guard source.
The owner of the city's Taj Mahal hotel, at the centre of last week's carnage, said he had also received a warning of a possible attack and had stepped up security.
There was also a report today that US intelligence had warned India of a possible attack at least a month ago.
Indian authorities say the militants who attacked Mumbai, killing more than 180 people, belonged to the Pakistan-based Lashkar-e-Taiba (L-e-T) group, also blamed for an attack on India's parliament in 2001.
"Yes, the coast guard and navy did have intelligence inputs that an L-e-T boat was to land in the creeks off the northwest Gujarat coast," a top coast guard official said, referring to the western state which borders Pakistan.
He said he had received a warning three days before the attacks. Gujarat is to the north of Maharashtra state, of which Mumbai is the capital.
Intelligence sources told the NDTV news channel they had issued a series of warnings of a possible attack on Mumbai by sea in the months leading up to last week's strike.
The latest, warning that the "sea wing" of Lashkar-e-Taiba was planning an attack, was issued on November 18th, just eight days before the militants struck, the TV channel said.
An earlier intelligence report warned that the Gateway of India monument and the Oberoi-Trident hotel were among the possible targets, NDTV said. The owner of the Taj Mahal hotel confirmed he had also been warned.
"It's ironic that we did have such a warning, and we did have some measures too, you know, where people couldn't park their cars in the portico where you had to go through a metal detector," the Taj's owner Ratan Tata told CNN.
"But if I look at what we had, which all of us complained about, it could not have stopped what took place. They didn't come through that entrance. They came from somewhere in the back," he said.
The militants appeared to have dodged the coast guard by hijacking an Indian fishing trawler, officials said.
India had suffered a series of bomb attacks on its cities even before the Mumbai attacks, and since 2004 has trailed only behind Iraq in terms of lives lost to attacks by militants.
Fishermen are sometimes seen as the eyes and ears of the coast guard in India. The leader of Maharashtra's leading fishermen's union says he had also tipped off the government some four months ago about militants using sea routes to land RDX explosives in Mumbai with help from the city's underworld.
"No one acted upon our information," said Damodar Tandel, the president of Maharashtra fishermen's committee.
Mr Tandel said the information came to him from fishermen in neighbouring Gujarat.
Pakistan offered today to help India investigate the militant assault on Mumbai and said it would "frame a response" to an Indian demand that it hand over 20 of India's most wanted men.
India has blamed Islamist militants based in Pakistan for the attacks in Mumbai.
Pakistan has condemned the assault, denied any involvement by state agencies and vowed to work with India in its investigation. Yesterday, it rejected what it called unsubstantiated allegations of complicity.
Tension between the two countries over the attacks has led to fears of renewed confrontation after Pakistan's civilian government had been trying to push forward a tentative peace process.
Foreign minister Shah Mehmood Qureshi, speaking in a televised address, repeated a Pakistani offer of cooperation, saying it was not the time for a "blame game, taunts (and) finger-pointing".
"The government of Pakistan has offered a joint investigating mechanism and a joint commission to India. We are ready to jointly go into the depth of this issue and we are ready to compose a team that could help you," Mr Qureshi said.
"Pakistan wants good relations with India," he said.
Earlier, Indian foreign minister Pranab Mukherjee told reporters India was demanding the handover of about 20 fugitives it believes are in Pakistan.
The demand was contained in a protest note handed to Pakistan's ambassador in New Delhi yesterday, Indian foreign minister Pranab Mukherjee told reporters, as tension mounted after the Mumbai attacks.
"We have to look at it formally once we get it and we will frame a response," Pakistan’s information minister Sherry Rehman told reporters in Islamabad.
Mumbai police said today they were interrogating many suspects in the attacks on India's financial capital but had not arrested anybody other than the one Islamic militant captured alive.
Mumbai's Police Commissioner Hasan Gafoor also dismissed speculation that more than 10 militants had been involved in the rampage on two luxury hotels, a railway station and a Jewish centre.
"There have been no arrests so far except the one terrorist we have detained. We are interrogating many suspects," Mr Gafoor told a news conference, the first since the attacks.
Reuters