At least one person was killed in an explosion in Assam - the third blast to have rocked the state on Tuesday after separatists bombed a goods train and triggered a blast near a market, as Britain, the US and Australia asked their nationals to keep away from the region.
A police spokesman said the third blast took place near the crowded Adabari market in Assam's main city of Guwahati around 6.30 pm.
"A shopkeeper spotted an unidentified can kept near the pavement and while he was trying to dispose the bomb it went off blowing him into pieces," a police official said.
The blast wounded 12 people, most of them evening shoppers or vendors, who were shifted to a local hospital.
"Three of the 12 injured are in a critical condition," the official said.
Earlier in the day, separatists triggered two explosions including a powerful blast on a goods train in the state.
Police said no casualties were reported in the two blasts although a wagon of the train carrying fertilisers was damaged. Railway officials said the blast took place near Lailalong in eastern Karbi Anglong district, about 310 km from in Guwahati.
"A wagon was damaged and a portion of the railway track was blown up in the blast creating a big crater," T Rabha, a spokesman for the Northeast Frontier Railways, said.
A packed passenger train was to cross the area soon after.
"The target was definitely the Kamrup Express although the militants failed to plant the bomb in time due to tight security vigil," the official said.
Suspected separatist guerrillas also triggered a blast near a market in Barabazar in western Assam's Bongaigaon district, about 210 km from Guwahati.
"There were no people around the place where the blast took place and hence no casualties reported," a police official said.
Two people were injured when rebels lobbed a grenade on late Monday at a group of people standing outside a fuel station at Changsari, about 35 km west of Guwahati.
"Two people waiting near the edge of the petrol pump were injured," a police official said. They were admitted to a hospital.
In the past nine days, 10 people have been killed and 54 wounded in 11 explosions, including three of Tuesday, in this oil, tea and timber-rich state.
The bombings were preceded by the slaughter Jan 5-8 in eastern Assam by separatist guerrillas of 73 people, 61 of them being Hindi-speaking migrants.
Authorities have blamed the outlawed United Liberation Front of Asom (ULFA) for the attacks. ULFA, however, has denied its involvement.
The attacks followed threats by ULFA asking migrant workers, most of them from Bihar, to quit Assam on the ground that they were taking away local jobs.
Meanwhile, Australia, Britain and the US have issued advisories asking their nationals to review travel plans to Assam.
"This warden message is issued to alert US citizens travelling to and residing in northeastern India, and especially Assam, of the serious security threat due to a series of recent killings and bomb attacks," said an alert posted on the website of the US Consulate General in Kolkata.
Similar alerts have been issued by Australia and Britain.
More than 10,000 people have lost their lives to insurgency in Assam during the past two decades.