New Delhi - The Indian police have issued sketches of three more men who are suspected to have planted the bombs that killed at least 63 people in northern Jaipur city, officials said Friday.

The police released the sketches late on Thursday night, based on the descriptions of witnesses, particularly owners of shops from whom bicycles used in Tuesday's serial bombings were procured.

Investigators who issued the sketch of the first suspect earlier on Wednesday believe that the terrorists had strapped explosives on bicycles to carry out the nine blasts that left 150 wounded.

"We have questioned about 15 to 20 witnesses for preparing these sketches. More sketches of suspects could be released shortly," senior city police officer HG Raghvendra told reporters.

Although no arrests were made, police said it had intensified investigations into the bombings in the city, capital of north-western Rajasthan state located 250 kilometres south-west of New Delhi.

Local media quoting police sources reported that the police believe that two terrorists each went to eight shops in local markets and bought 10 bicycles which suggested that 10 or more terrorists were behind the bombings.

Meanwhile, the Indian Express daily reported that 35 Bangladeshi nationals were detained across Rajasthan for questioning in connection with the attacks.

Although a little-known terrorist outfit called the Indian Mujahideen claimed responsibility for the attacks, the Indian media reported that the role of Bangladesh-based Muslim militant group Harkat-ul Jihadi-e-Islami (HuJI), was being suspected in the carnage.

The police was also questioning a hotel owner in the state's Udaipur city who claimed one of the suspects had come to his hotel a day before the blasts.

Indian security agencies blame the HuJI for carrying out serial bombings in northern Uttar Pradesh in November 2007 which left 13 dead and wounded over 40. The same terrorist group was suspected in a bomb attack at a Sufi Muslim shrine in Ajmer last year which claimed two lives. (dpa)