Both Pakistan and India blamed each other for starting the fire that began Friday night. This latest violence comes after Islamabad accused Indian forces of killing two of its soldiers Wednesday in a crossfire that also killed an Indian soldier.

In a statement Saturday, the Pakistani military said that Indian forces violated the cease-fire agreement between the two countries with an unprovoked barrage of artillery Friday night near the city of Sialkot. It said Pakistani soldiers returned fire.

Indian border guard officials said Saturday that Pakistani troops first opened fire Friday on 20 Indian posts in Samba and Kathua sectors across the international border.

"The firing began Friday evening. Intermittent exchange of gunfire and shelling is still on," said a Border Security Force official on condition of anonymity as he was not authorized to talk to journalists.

Shantamnu, a top Indian state government official who goes by one name, said Pakistani fire wounded at least four civilians.

On Friday, Sartaj Aziz, a security and foreign affairs adviser to Pakistan's prime minister, wrote a letter to India to protest the killing of the two Pakistani soldiers Wednesday and called for "an immediate investigation into the incident and bringing the perpetrators to account," according to a Foreign Ministry statement. Pakistan says the two slain soldiers had been invited for a meeting with their Indian counterparts.

Kashmir is claimed by both India and Pakistan. The two countries have fought two wars over the Himalayan region since they won independence from Britain in 1947.

While minor skirmishes between Indian and Pakistani troops are common along the 200-kilometer (125-mile) border, the worst violation of the cease-fire accord took place in October over the Muslim holiday of Eid al-Adha and killed nine civilians in Pakistan and nine in India.