Security forces in Indian-administered Kashmir say they have shot dead three men who stormed a police station and an army camp, killing at least 10 people.
The gunmen were wearing Indian army uniforms when the attacked the station in Kathua district and the base in Samba district, said police.
Kashmir has seen an armed insurgency against Indian rule since 1989.
Indian Prime Minister Manmohan Singh described the attack as barbaric, but said it would not derail peace efforts.
He is due to meet his Pakistani counterpart, Nawaz Sharif, on the sidelines of the UN General Assembly this week.
Peace talks between the two countries have been stalled for the past two years, and dialogue is expected to ease recent tensions along the Line of Control that divides Kashmir between the two countries.
India has a large security presence in Kashmir with tens of thousands of police and paramilitary forces deployed in the region.
On Thursday morning the attackers, dressed in army uniforms, arrived at a police station in Hiranagar in Kathua and opened fire.
Four policemen and two civilians were killed in the attack, police said.
The militants then hijacked a truck and fled, senior Kashmir police official Rajesh Kumar told Reuters news agency.
"They abandoned the truck on the national highway and perhaps took another vehicle and carried out an attack on the army camp in Samba," he said.
Jammu and Kashmir Chief Minister Omar Abdullah told reporters that the attackers had crossed over from Pakistan on Wednesday.
"Given the history, timing and location, the aim is to derail the proposed meeting between Prime Minister Manmohan Singh and his Pakistani counterpart," Mr Abdullah said.
"There are forces that are inimical to peace and want to derail any peace process."
Earlier this week, a paramilitary soldier was killed when suspected militants fired at two soldiers in a busy market in Srinagar.
In recent years violence in Kashmir has abated from its peak in the 1990s, but the causes of the insurgency are still far from resolved.
And the hanging earlier this year of a Kashmiri man, Afzal Guru, on charges of plotting the 2001 attack on India's parliament, has triggered a fresh spate of violence.
In May, four soldiers were killed in an ambush by suspected militants in Pulwama district.
In March, two armed militants disguised as cricket players attacked a paramilitary camp and killed five troops.
The militants were killed in retaliatory fire. Two people were arrested in connection with the attack.