Rival political parties on Saturday wrangled over a special mass organized by the left-leaning Catholic Priests' Association for Justice that called for the resignation of President Park Geun-hye.

The gathering held at the southwestern city of Gunsan demanded that Park take responsibility for the alleged intervention in last year's presidential race by the country's spy agency.

The ruling Saenuri Party lashed out at the priests by pointing out that they are effectively rejecting the legitimacy of a fairly elected chief executive chosen by the people.

"This shows clearly that they have ulterior (political) motives," claimed party spokeswoman Min Hyun-joo.

She then pointed out that comments by some priests at the gathering were highly regretable and not the kind of comments befitting people of the cloth.

Media reports said a priest at the gathering seemingly took the North Korean side in regards to the shelling of Yeonpyeong Island three years ago that left four people dead.

Park Chang-shin from the Jeonju diocese not only called for Park to step down and her predecessor Lee Myung-bak to be arrested, but hinted that the North had the right to fire at the island.

He argued that just as South Korea would react to Japan carrying out a military exercise near Dokdo islets in the East Sea, Pyongyang had only take countermeasures to the South Korea-U.S.

military drill along the sea demarcation line between the two Koreas. Dokdo is South Korea's easternmost territory.

Min said such a remark is an affront to the people and those who died in the tragedy.

She then said religious leaders should abstain from making comments that break up the country, and refrain from engaging in trying to shake the government.

"Such a move will never shake the legitimacy of the administration," the lawmaker said.

The presidential office also said the mass raised disturbing questions.

Senior presidential press secretary Lee Jung-hyun told reporters that comments made by some priests show they have trouble determining which country they belong to.

"The Park administration is firmly committed to adhering to the core values of the country," he said, emphasizing that Seoul will remain true to defending the country and protecting its people.

On the other hand, the opposition Democratic Party (DP) said the presidential office of Cheon Wa Dae should heed the warnings.

"The mass showed how irresponsible the administration has been towards allegations of foul play and how reluctance it has been to face up to the seriousness of the allegations raised," said party spokesman Park Yong-jin.

He said the presidential office and the ruling Saenuri Party are trying to paint an image that the priests who organized the mass are trying to drive a wedge in society.

"If the ruling camp is unwilling to listen to the priests, it is questionable whether they can strive for national unity," the DP official said.

Park said it is the National Intelligence Service (NIS), the Saenuri and the Cheong Wa Dae that are fueling social discord by dragging their feet at trying to unearth the truth about the election irregularities.

Meanwhile, Saenuri and the DP collided on the need to appoint a special prosecutor to investigate allegations of the NIS election meddling.

The ruling party argued that the DP is only interested in opening the probe by the special council because it wants to politicize a case that can easily be handled by the state prosecutors office.

"There is nothing that a special prosecutor can unearth that has not already been discovered by investigators assigned to the case," a party official said.

He said the DP should stop making unrealistic demands and come to the negotiating table to deal with pressing issues facing the country.

On the other hand, the DP said the ruling camp must accept the appointment of a special council if it wants to resolve the impasse.

It also demanded the establish of a committee to oversee reforms of the NIS.

The liberal party then blasted the way the president continued to rely on a handful of people to run the country and handing out public appointments to those that supported her in the past.