WASHINGTON - PAKISTAN President Asif Ali Zardari on Tuesday strongly denied his country was involved in the Mumbai attacks, saying the gunmen were 'stateless actors' seeking to hold the world hostage.

'I think these are stateless actors who have been operating throughout the region. The gunmen, whoever they are, they are all stateless actors who are holding hostage the whole world,' he told CNN's Larry King.

'The state of Pakistan is no way responsible,' the Pakistani leader said, in an excerpt of the interview, when asked about the attacks by 10 gunmen which left 188 people dead and more than 300 injured.

Pakistan on offered on Tuesday to work hand-in-hand with India to track down those behind the attacks, but did not respond to a demand to hand over 20 suspects to Delhi.

Mr Zardari added that he doubted Indian claims that the sole surviving gunman, who was captured by Indian security forces during the 60-hour siege of the city, was a Pakistani.

'We have not been given any tangible proof to say that he is definitely a Pakistani. I very much doubt, Larry, that he's a Pakistani.'

Pakistan's Prime Minister Yousuf Raza Gilani has said his government wants proof of India's allegation that all the attackers were Pakistanis.

CNN and other US networks has reported that the United States had warned India in October that hotels and business centers in Mumbai would be targeted by attackers coming from the sea.

'Sophisticated' bombs used
Militant groups that waged war on Mumbai last week planted a total of five bombs during the attacks, two of which were 'sophisticated,' the US television network ABC News reported, quoting police in India on Tuesday.

At least two of the bombs 'used sophisticated timers unlike anything India had seen until this year', ABC said.

Two bombs exploded on Wednesday night in taxis in seperate Mumbai suburbs, while one was found outside at the Oberoi/Trident hotel and two outside the Taj Mahal Palace hotel.

Both of the Taj bombs were discovered to have a sophisticated electronically-programmed timing device, similar to those in bombs planted in July in the western Indian city of Surat.

Police defused one of the bombs outside the Taj, which a bomb squad determined had been set to explode early on Thursday.

'I think they wanted to blow up the maximum number of people, including security forces, media people, and any guests evacuated from the hotel,' Steven Anthony, top investigator for the Mumbai police bomb squad, told ABC.

Fellow bomb squad officer Sachin Gawade said that some of the bombs appeared to contain around 17 pounds of a 'greasy, black' RDX explosives 'very similar to the explosives found in the bombs used during the 1993 Mumbai blasts', which killed 257 people. -- AFP