NEW DELHI, Jan 19: Top military officials of India and Pakistan on Wednesday talked over the phone on the incident of firing from across the Line of Control in Jammu and Kashmir, defence officials said.

Delhi termed the incident as violation of the cease fire agreed in November last year, and expressed its concern over the development.

"The Director General of Military Operations (DGMO) spoke to his (Pakistani) counterpart at 9:30 this morning telling him about our concerns on this particular issue ... this is the first time when weapons of these calibre have been opened up since the ceasefire came into being," Lt Gen B S Thakur, who took over as Vice Chief of Army Chief today, told reporters when asked about the firing of mortar shells in Poonch sector allegedly by Pakistani troops last evening.

"The Pakistan DGMO first said he had also heard of some firing but he was not aware who fired them. But when we gave them the details of the exact position where the firing had come from and where it landed, he promised to investigate it and then come back to us on this," Gen Thakur said.

The new Vice Army Chief said India considered the firing "as a violation of the cease fire", which came into effect in November 2003. However, he said: "We will maintain restraint and have not retaliated. We hope the Pakistan government will consider this case with all seriousness."

Indian news reports said Pakistan has agreed to investigate reports of mortar firing. Most accounts say 13 mortar rounds were fired on an Indian post on Tuesday evening, shattering the calm that prevailed since the Indo-Pakistan cease fire of Nov 25, 2003.

"Around 12 to 13 mortar bombs were fired across us. We also heard shouts of Allah-o-Akbar said Lt-Gen Hari Prasad, Northern Army Commander told NDTV. "There has been no response from our side. Our troops are vigilant and we are ready for any response. We exercised tremendous restraint," Lt-Gen Prasad said.