High explosive RDX was used in the terror strike in Jaipur, a senior police official said on Wednesday as tell-tale signs pointed towards the involvement of Bangladesh-based Harkat-ul-Jihadi Islami in the serial blasts.

The explosive devices were fitted with timers and planted on cycles, a modus operandi similar to the one used in last year's blasts in court premises in Uttar Pradesh in which HUJI was involved, the police said.

Eight persons including a man injured in the blasts and a rickshaw puller are being questioned, they said, noting that seven teams of Rajasthan police and intelligence branch have begun the probe into the blasts.

"It was a cent per cent a terrorist attack on the pattern of blasts in the court premises in UP in November last year. RDX was used in containers tagged to cycles along with timer devices," Additional Director General of Police (Crime) A K Jain said.

An examination of the blast sites indicated that the bombs were filled with ball bearings and small iron pieces to act as splinters, sources close to the investigation said.

HUJI may have been able to form sleeper cells in Rajasthan, they said, adding that a proper investigation into the blast at a Sufi shrine in Ajmer last year could have been a pointer.

"We have collected sufficient evidence from the places of the blasts. They are being analysed by our technical experts," Superintendent of Police, Jaipur, Raghvendra Suhasa said, noting that one unexploded bomb, found from the blast site, has been defused.

Union Home Secretary Madhukar Gupta told reporters in New Delhi that "our priority now apart from vigilance and being on the alert will be to get hold of the people reponsible" for the blasts.

The sources said the blasts triggered in areas close to two Hanuman [Images] temples in the old city could have been aimed at disturbing communal peace.

Rajasthan's Home Minister Gulab Chand Kataria said the state has requested the Centre for additional forces to maintain peace.

"We have asked for some forces including some commando units from the Centre as the blasts were clearly aimed at flaring up communal passions in the state," he said.

Police sources said that investigations were on to find out from where the cycles, which were new, were purchased.

Asked whether the state had any prior information about the blasts from intelligence agencies, the minister replied in the negative.

Eight serial blasts took place in a span of 12 to 13 minutes in crowded market areas of Jaipur leaving 63 dead and 200 injured.

The blasts rocked Tripolia Bazar, where large number of devotees had turned up at a Hanuman temple, Johari Bazar, Manas Chowk, Badi Choupal and Choti Choupal -- all located within a two-km radius in the old city.

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