A bomb has exploded at an Independence Day march in the north-eastern Indian state of Assam, killing at least 18 people and injuring many others.
Police said many of the victims of the blast on a college parade ground in the town of Dhemaji were schoolchildren or their mothers.
Local people incensed at the failure to protect the parade later attacked police vehicles at the scene.
Police sources blamed the attack on one of Assam's eight separatist groups.
The United Liberation Front of Assam (Ulfa) had called for a boycott of Independence Day events.
The blast occurred at 0930 (0400 GMT) in the town 460km (285 miles) east of the state capital, Guwahati.
"There was total panic with people running all over the place crying for help,"
Jatindra Nath, a government official who was at the parade ground,
told AFP news agency afterwards.
"I could see scores of people profusely bleeding and lying on
The blast came after two other attacks in the state:
- a small explosion also blamed on the Ulfa was reported in Dhubri on Saturday evening
separatists were blamed for a grenade blast at a cinema on Saturday which killed four people in Gauribari
Rebels have been fighting for independence since 1979 in a struggle which has claimed more than 10,000 lives.
Security was tight across India for the celebrations.
In the capital, Delhi, helicopters clattered overhead while nearly 65,000 police and paramilitary troops were deployed.
This woman was one of the many injured
In a speech to mark the 57th anniversary of independence from British rule, Prime Minister Manmohan Singh said India would continue to pursue dialogue with arch-rival Pakistan.
"It is our intention to carry forward with firm resolve and sincerity the composite dialogue process with Pakistan," he said, adding that peace should be built on the twin pillars of mutual trust and confidence.
But Mr Singh, speaking from a bullet-proof enclosure in the 17th-Century Red Fort complex, also warned that "cross-border terrorism" risked marring the process.