India said Wednesday a soldier was killed during heavy cross-border firing with Pakistan, which the army described as among the worst since a ceasefire agreement a decade ago.

India's paramilitary Border Security Force (BSF), which patrols the internationally recognised border south of the disputed frontier in Kashmir, said one soldier had been killed and six injured in overnight firing.

BSF spokesman Vinod Sharma told AFP that 50 frontier posts were targeted in a further escalation of small arms firing and shelling that has taken place regularly over the last month -- despite public pledges to ease tensions there.

Indian army spokesman Nitin Narhar Joshi told AFP the flare-up is among the worst since 2003, while senior army commanders speaking on condition of anonymity said it was the most serious.

"The situation along the LoC is certainly one of the most serious witnessed since the ceasefire," Joshi said. "Now it is becoming ever worse with the sanctity of the international border also being severely violated by Pakistan."

Firing along the disputed Line of Control (LoC) that separates Kashmir into Indian and Pakistani sectors has taken place sporadically ever since 2003.

But the recent rise in incidents has caused alarm. The subject was taken up by Prime Ministers Manmohan Singh and Nawaz Sharif at the UN in New York last month when they pledged to improve conditions to build trust.

India's defence ministry says it has compiled more than 200 ceasefire violations this year, more than all the other violations since 2003.

Pakistan's military responded on Wednesday blaming Indian troops for the uptick in cross-border firing.

"Indian BSF also targeted 27 Pakistani posts in last two days and fired almost 4000 mortar shells and 59000 rounds of machine guns," it said in a text message sent to AFP, adding that Pakistani troops effectively responded to Indian firing.

"During last two weeks, due to Indian shelling two civilians and a Rangers soldier have embraced Shahadat (martyrdom) and 26 civilian have been injured on working boundary and LoC," it added.

Sharif is currently in Washington and is set to meet President Barack Obama later Wednesday, after angering India by calling for US involvement to help settle the six-decade dispute over Kashmir.

The BSF's operations chief in New Delhi, Raju Krishna, repeated longstanding Indian suspicions that cross-border firing is aimed at helping Islamist militants from Pakistan infiltrate into Kashmir.

"We are giving a befitting reply to prevent the infiltration bid," Krishna told AFP.

The Muslim-majority Himalayan region of Kashmir is divided and administered separately by India and Pakistan but claimed in full by both.

It has triggered two of their three wars since independence from Britain in 1947.

Indian Foreign Minister Salman Khurshid last week described the military flare-up as a "serious matter".