India's Republic Day has been marred by violence in north-eastern Assam state.
Bombs in Guwahati, Assam, targeted a Republic Day parade
Suspected separatists exploded five bombs, while police said they killed two people after a patrol was attacked by a mob.
Elsewhere, Indian-administered Kashmir virtually shut down while Maharashtra cancelled celebrations after a stampede that killed at least 250 pilgrims.
Security was intense in the capital, Delhi, as India showed off its military hardware in a huge parade.
Republic Day has in the past been targeted by separatist groups rejecting Indian rule.
Police in Assam said a military patrol hunting separatists on Sialmari island on the Brahmaputra river killed at least two people after being attacked by a mob.
The Delhi parade showed India's cultural diversity
Assam police intelligence chief, Khagen Sharma, told the BBC's Subir Bhaumik in Calcutta that the troops tried to reason with more than 100 villagers.
But he said a melee ensued and troops opened fire after two colleagues were hurt.
Assam authorities also said two bombs exploded in Hajo district and another in Bongaigaon district.
Two more went off in state capital Guwahati, injuring at least four policemen, despite heavy Republic Day security.
One blast was about 200 metres from where Assam Governor Ajai Singh was sitting for a parade.
Chief of the military wing of the separatist group, the United Liberation Front of Assam (Ulfa), Paresh Barua, said it carried out the attacks.
Ulfa is one of more than 20 rebel groups fighting for greater degrees of independence or tribal rights in India's north-east.
Guest of honour
In Delhi, more than 20,000 security personnel were deployed for the country's biggest parade.
A cadet salutes in Srinagar and, right, a stallholder following the Maharashtra fire and stampede
Tanks, planes and helicopters paraded past President APJ Abdul Kalam and guest of honour, Bhutan's King Jigme Singye Wangchuck.
Floats and dancers representing India's different cultures were also involved in the 90-minute event.
In Indian-administered Kashmir, about 500 people attended the main parade in the summer capital, Srinagar.
The BBC's Altaf Hussain in Srinagar says security was heavily deployed within two kilometres of the Bakhshi Stadium, which hosted the event.
He says shops were closed and transportation shut down in the Kashmir Valley in response to a call by separatists fighting Indian rule.
The separatists have waged their armed campaign in Kashmir, which is claimed by both Pakistan and India, since 1989
On Wednesday, Pakistan's President Pervez Musharraf sent a message to his Indian counterpart, saying: "I sincerely hope our two countries will be able to resolve all outstanding issues... peacefully."
In India's western state of Maharashtra, the governor cancelled Republic Day celebrations following the death of more than 250 pilgrims at a stampede on Tuesday.
The tragedy was triggered by a fire during a pilgrimage to the remote Mandhar Devi temple.