New Delhi/Srinagar (PTI): For the second time in less than a week, Pakistani troops opened unprovoked fire on an Indian border post at Tangdhar in Northern Kashmir in a development which was described as "worrisome" by Prime Minister Manmohan Singh.

"It is worrisome," Singh said as the violation of the five-year-old ceasefire was taken up by the Director General of Military Operations (DGMO) through the hotline.

"India's concerns over the unprovoked firing were conveyed to his Pakistani counterpart," Defence Minister A K Antony said.

The Prime Minister voiced concern over the firing while talking to reporters on the sidelines of the Defence Investiture ceremony at Rashtrapati Bhavan.

"We have taken up the matter at the level of DGMO," Singh said making it clear that all issues having bearing on the Indo-Pak relations would be taken up during the forthcoming Foreign Minister level talks between the two countries.

Using heavy machine guns and mortars, Pakistani troops targeted a forward Indian post in the Tangdhar area raking it with 50 to 60 rounds last evening, army sources said here.

The Pakistani DGMO even expressed surprise at the incident, according to army sources.

Army sources said this was not a covering fire for any attempt to push in terrorists. It was targetted straight at the Indian post.

About eight to ten mortar shells were also fired which fortunately fell far short of the post.

"There was no casualty," an army spokesman said adding that Indian forces had exercised "extreme restraint" and had not opened retaliatory fire.

This is the first major violation of the ceasefire by the Pakistani troops on LoC which has been in force since December 2003.

The firing by the Pakistani troops from across LoC comes close on the heels of Pakistani Rangers breaching the ceasefire on the international borders near Samba earlier this week.

At the talks between the two DGMOs, it has been decided to have a flag meeting to take up the issue, army spokesman said.

In Islamabad, however, Pakistani military inter-services spokesman denied that its troops had fired at the Indian post.