JAIPUR, India (Reuters) - Police probing bombings inwestern India that killed 63 people said on Friday that newevidence pointed increasingly towards Indian Islamists backedby a Bangladeshi militant group as being behind the blasts.

Nine bombs, all strapped to bicycles, ripped through acrowded shopping area in the popular tourist city of Jaipur onTuesday evening. Another 216 people were wounded.

Investigators said the attack bore hallmarks of theBangladeshi militant group Harkat-ul-Jihad al Islami (HuJI),suspected to be behind several previous blasts in India.

"The modus operandi of the entire operation, the way thebombs were manufactured and concealed in bags are very similarto the way HuJI operates," Pankaj Singh, a senior policeofficer in Rajasthan state where the attacks happened, toldReuters.

"It is very possible that Indian groups helped them," Singhsaid in Jaipur.

Rajasthan's Parliamentary Affairs Minister R.S. Rathoresaid on Friday that 18 people, mainly Bangladeshi migrants,were being questioned by police. He also said the latest tollwas 63 dead.

India has suffered a wave of bombings in recent years, withtargets ranging from mosques and Hindu temples to trains. Butfew groups have ever claimed responsibility for the attacks.

Islamist militant groups in Pakistan and Bangladesh intenton fanning hatred between Muslims and Hindus in India, anddamaging a fragile peace process between New Delhi andIslamabad, are often blamed for bomb attacks in India.

Bangladeshi officials said India should not jump toconclusions.

"While we don't rule out the existence of HuJI inBangladesh we can say their activity has been drasticallycontrolled by the security agencies here," Hasan MahmoodKhandaker, director general of the Rapid Action Battalion, toldReuters.

Indian police said they were now looking for Indiansuspects and have released several sketches of people who couldhave been the bombers and the ones who bought bicycles inJaipur.

An email to local media, from a group calling itself theIndian Mujahideen, claimed responsibility for the attack.Similar claims were made minutes before a blast in UttarPradesh state last year.

The email also included a video of a bicycle with a bagstrapped to it and showed the bike's serial number, which thepolice said matched with one of the bicycles from the blastsite.

Indian police said they were taking the email "veryseriously," although some police officers and the chiefminister have questioned its authenticity.

"Some portions of the email are definitely true, someappears to be wrong and is an attempt to misleadinvestigations," Singh said. "But they did get the serialnumber right."

In the email, the Indian Mujahideen declared open war onIndia and threatened more attacks on tourists.

"From the tourism point of view, this attack is to warn theentire crusaders of the world, U.S. and Britain in particular,we Muslims are one across the globe and you won't find it easyin India as well," the email, obtained by Reuters, said.

"Don't send your people to India and if you do so then youpeople will be welcomed by our suicide attackers," it said."This letter is an open warning to India that stop supportingU.S. in the international arena."

WORRIED TOURISTS

Many foreign tourists said they were scared and wereleaving Jaipur, in spite of the police assuring them of safety.

"We saved a lot of money working and then decided to spendquality time in Jaipur, but it has been a shame that we havebeen stranded in the hotel most of the time," said Samuel andEmily, a young couple from Southampton in England. "We aregoing back."

Some foreign tourists said they have not been able to shopor move freely inside Jaipur, also known as the pink citybecause of the colour of its ancient buildings.

"We are very unhappy, we could not shop," said one tourist,as he boarded a bus along with a group of Americans.

Armed police patrolled the streets of Jaipur's famous oldcity.

Some local people who have not been able to trace theirrelatives since the blast were scouting hospitals.

"We have not been able to find our 15-year-old Dasarath. Hedid not return home that night," a sobbing relative said.

In the past few years, bomb blasts in Indian cities havekilled hundreds of people. The deadliest was in July 2006, whenseven bombs on Mumbai's rail network killed more than 180people.

(Additional reporting by Ruma Paul and Masud Karim inDhaka; Editing by Alistair Scrutton; Editing by David Fogarty)