A woman mourns the death of her father in the blast in Nalbari on Sunday. (AP)

Nalbari, Nov. 22: Back-to-back “cycle bomb” explosions left six people dead and over 50 injured in Assam’s Nalbari town this morning, the first blast a decoy that attracted a crowd before the second delivered the killer blow.

The twin blasts were the first to be triggered through bicycles that had been converted into bombs — rather than being fitted with bombs as seen elsewhere in India — by stuffing explosives and ball-bearings inside their hollow metal frames.

The first, low-intensity explosion occurred around 10.05am in front of a paan shop within 50 feet of the main police station in the district town, about 70km west of Guwahati. It injured a handful of people, none seriously.

As a crowd gathered — the area is the town’s commercial hub — the second bomb went off 10 minutes later in front of a restaurant about 80 feet away, killing five on the spot and injuring about 50, one of whom later died.

A similar cycle bomb had been seized from a suspected Ulfa cadre in March last year but this is the first time such a bomb had been detonated.

Nalbari superintendent of police Jitmal Doley said bicycles were checked regularly. “We check the bags that riders carry but it is difficult to detect explosives that may be inside the cycle frames,” he said.

Inspector-general of police (law and order) Bhaskarjyoti Mahanta said the blasts had “Ulfa written all over it” and that the outfit had targeted police. However, no police personnel was killed or injured.

A caller claiming to be the local Ulfa commander told the media his outfit “was in no way involved”, although the outfit is known to carry out attacks in the run-up to November 27, the day it was banned 19 years ago.

The police had blamed Ulfa and Islamic militants also for the serial blasts across several Assam towns on October 30 last year, but they were later pinned on a National Democratic Front of Boroland faction.

Doley said all angles were being probed and intelligence officials suggested the Bodo militants were the more likely suspects.

The blood-stained blast sites were littered with ball-bearings of various sizes and discarded footwear. Among the dead was the gaonburha (village headman) of Nalbari town, 78-year-old Mohabbat Ali who lived about 200 metres from the police station.

“Father went out to enquire after the first blast,” said his son Muhib. “I went out after hearing the second explosion and found him lying blood-splattered. We rushed him to hospital but he died.”

If the first blast drew many like Ali to their death in the second, it saved paan shop owner Boloram Roy, who is in his late 30s.

Roy was having his hair cut in a salon when the first bomb went off in front of his shop. He rushed out to see if his shop had suffered damage, escaping the second bomb that exploded yards from the salon, killing the barber, Paban Thakur. “He (Thakur) was talking to me just a few moments ago, joking about my thinning hair as he was snipping it,” Roy said.

The People’s Committee for Peace Initiatives in Assam, which is pushing for a peace process with Ulfa, condemned the blasts, as did chief minister Tarun Gogoi, who is in Delhi.

The attack broke a lull of several years in Nalbari, a one-time hotbed of Ulfa activity.