The cross-border firing occurred at the Hiranagar sector on the International Border and Naushera on the Line of Control (LoC) in Rajouri district of Jammu division.
The civilians - two girls and a man - were injured in Hiranagar, a police spokesperson said. The victims suffered mortar shell splinter injuries in Lallai Chak village.
Heavy mortar shelling by Pakistan Rangers continued till 6 a.m. in Lallai Chak, Pansar, Pahadpur and Londi villages where over two dozen houses were also damaged, the spokesperson said.
Over a dozen cattle perished in the villages.
The Border Security Force (BSF) retaliated and targeted an unknown number of Pakistani posts across the boundary.
There was no injury in the cross-border shelling in Naushera on the LoC - the de facto border that divides Jammu and Kashmir between India and Pakistan.
"The Pakistani Army resorted to unprovoked ceasefire violation using 82 mm and 120 mm mortars, automatics and small arms to target our positions on the LoC in Naushera," defence Spokesman Lt Colonel Manish Mehta told IANS.
"Our troops are appropriately and effectively responding," Mehta said.
"The firing and shelling were still going on in the area. There was no casualty or damage on our side," the spokesman said.
India and Pakistan have accused each other of regularly violating the 2003 ceasefire agreement between them.
India shares 230 km of International Border and 740 km of LoC with Pakistan in Jammu and Kashmir.
The boundary, manned by the paramilitary BSF runs through Jammu district and the LoC, which is not an internationally-accepted frontier, cuts across other regions of the state.
Border skirmishes have occurred occasionally since the truce was signed 13 years ago.
But ceasefire violations intensified after Pakistani militants attacked a military base in Jammu and Kashmir's Uri, killing 19 Indian soldiers on September 18.
The Uri attack prompted the Indian Army to carry out a surgical strike that destroyed seven terror launch pads and killed an unknown number of terrorists and their sympathizers in Pakistan-administered Kashmir.
Heightened border tensions between the two countries have forced many residents of border villages to migrate to safer locations.
According to official estimates, over 400 families have migrated from border areas to safer locations in Jammu.
In Abdullian village of the R.S. Pura sector, entire population was said to have also migrated after Pakistan Rangers targeted civilian and BSF facilities in the area during the last five days.