Political tensions intensified Tuesday as the main opposition New Politics Alliance for Democracy boycotted parliamentary sessions in protest against the government and the ruling party’s final decision to adopt state-authored textbooks.

But the ruling Saenuri Party urged the NPAD to return to the National Assembly and focus on legislative works, denouncing the opposition for crippling the Assembly by preventing the legislature from passing pending bills that the ruling party said would boost the nation’s economy.

The partisan standoff is expected to persist for days as the NPAD vowed to continue its boycott of the parliamentary sessions -- including plenary sessions scheduled for Tuesday and Thursday and an ongoing parliamentary review for the 2016 budget -- unless the government withdrew the plan.

“(The government) ignored the overwhelming majority of the public and turned a deaf ear to the people’s plea. They have shut down fax machines since Monday afternoon and rejected oppositions’ messages,” said NPAD leader Rep. Moon Jae-in at the Assembly’s hall where fellow party members staged a sit-in.

They were holding the parliamentary sit-in for the first time since the Sewol disaster that claimed hundreds of lives last April. They called the government’s reinstatement of state textbooks a “dictatorial” move. The NPAD lawmakers have yet to decide when to end their protest.

Reluctant to hold talks with the Saenuri Party’s leadership -- an event that was scheduled for Wednesday to discuss the parliamentary impasse -- the NPAD pledged to continue its opposition, with such plans as filing a constitutional appeal and a campaign to gather signatures from those who oppose the policy.

The Saenuri Party denounced the boycott and blamed the NPAD for derailing parliamentary proceedings. The ruling party demanded the rivals stick to the legislative schedule to pass pending draft bills and finish budget reviews.

“Considering that the Assembly faces a busy and crucial moment, I feel it’s so regrettable that the NPAD boycotted the plenary session it had agreed to hold. I strongly urge the NPAD to let historians and other experts deal with the textbooks and return to its own legislative work,” said Saenuri Party whip Rep. Won Yoo-chul.

Meanwhile, municipalities’ top educators were divided over the textbook controversy. A group of liberal superintendents, teachers unions and college professors publicly criticized the government for reintroducing state textbooks, while some conservative educators supported it.

Kim Ji-cheol, the education chief of South Chungcheong Province, said in a statement Tuesday that he regretted that the government had pushed through the process in what he described as an attempt to undermine diversity in public education.

Some branches of the Korean Teachers and Education Workers’ Union -- the nation’s biggest progressive teachers’ union -- issued a statement condemning the government’s move. About 100 professors from Gangwon National University announced their protest in a public statement.

Conservative superintendents such as Daejeon’s education chief Seol Dong-ho, however, endorsed the government policy, saying that the municipality would follow the government’s decision if it decided to author the textbooks.

By Yeo Jun-suk (jasonyeo@heraldcorp.com)