North Korea may carry out a live fire exercise during the key party congress that kicks off Friday as part of its ongoing effort to ramp up tensions and get the people to rally behind its leader, an informed source said.

The government insider said there is a chance that Pyongyang could show off an artillery attack against a mockup Cheong Wa Dae, South Korea's presidential office, to participants who have converged on the capital city this week to take part in the critical Workers' Party of Korea (WPK) event.

The congress is the WPK's highest-level political guidance body and comes after the North detonated its fourth nuclear device in January and fired off a long range missile in the following month that triggered the toughest United Nations sanctions to date. It also comes amid concerns the reclusive country will show its disdain for international sanctions by testing another nuclear weapon.

This year's congress is the first since October 1980, and the first under Kim Jong-un who assumed power in late 2011 following the sudden death of his father, Kim Jong-il. 

"We are watching if the North will invite senior party members attending the congress to witness the drill," he said. "We are keeping close tabs on such a development."

The source said the exercise could take place right after the congress session, although he was not certain if a date had been set.

The communist country has yet to announce the duration of the congress with North Korean watchers in Seoul predicting it will run for three or four days.

The official, who declined to be identified, pointed out that the North has openly showed its animosity towards the South, and in particular President Park Geun-hye, by repeatedly threatening to blow up Cheong Wa Dae in the past.

On Feb. 24 the North's supreme military command issued a threat to obliterate Cheong Wa Dae, with similar threats being made twice in March.

South Korean intelligence has confirmed that the North has built a scaled-down replica of the presidential office at its Daewon-ri training range just outside of Pyongyang and has moved various artillery pieces to the area.

It said that some 50 artillery pieces, including 122 millimeter multiple launch rocket systems and towed howitzers, have been positioned a kilometer away from the mockup Cheong Wa Dae.

Observers said that the military may conduct a live-fire barrage that will reduce the replica presidential office to rubble, with the North state-run media to report the event to the general populace.

"The North may feel that such a move will help the people rally behind its young leader and fuel military tensions on the Korean Peninsula," another expert, familiar with the way Pyongyang conducts its affairs, said. (Yonhap)