SEOUL (Reuters) - Speculation that North Korean leader Kim Jong Un will soon visit Seoul for the first time has sparked debate in South Korea over how to allow citizens to express often strongly held views while preventing any international incidents.

To pull off the summit he wants – full of inspiring imagery of Korean unity and reconciliation - President Moon Jae-in needs to walk a fine line between providing sufficient security for Kim and being accused of stifling speech to appease a dictator.

Unlike tightly controlled Singapore, where Kim took a surprise night time stroll before his summit with U.S. President Donald Trump in June, Seoul is routinely roiled by protests.

Many South Koreans still take a dim view of North Korea in the wake of their 1950-53 war and decades of hostility, making the risk of disruptions to the visit high.

A summit in Seoul now appears unlikely this year, but small yet vocal groups of conservative protesters who routinely gather on Seoul streets to protest against Moon or to urge Trump to bomb North Korea have already mobilized to protest any visit by Kim.

At a recent rally in downtown Seoul, banners read “Let’s punish Kim Jong Un” and organizers said they intend to try to “arrest” the North Korean leader.

“Once (Kim) steps on our land he will be captured and no one can take responsibility for what will happen afterwards,” Ihn Ji-yeon, a leader with the far-right Korea Patriots Party told Reuters at the rally.

Seoul police declined to comment on those claims.

Opposing groups have also been vocal in wanting to welcome Kim and calling for more engagement with the North, encouraged by a relaxation in enforcement of national security laws.

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PREVENTING THE UNEXPECTED

At their summit in Pyongyang in September, Kim told Moon he would visit Seoul “at an early date”. South Korean officials pressed for it to happen this year, but they now say that appears unlikely.

Any summit in Seoul would likely be overshadowed by a lack of progress on negotiations between North Korea and the United States over Pyongyang’s nuclear weapons program.

That could leave Moon and Kim little leeway to progress their goals of declaring an official end to the Korean War, forging closer ties and resuming joint economic projects.

Kim’s visit would be the first by a North Korean leader to the South, so security forces of both sides would be treading on unknown ground.

The security office of South Korea’s presidential Blue House would likely oversee the whole operation, while North Korean security forces would conduct inspections ahead of time, as well as provide personal protection for Kim during the visit, said Lee Man-jong, a law and police professor at Seoul’s Howon University.

At the 2010 G20 summit, Seoul mobilized about 50,000 security forces, and about 35,000 for Trump’s state visit in November last year, Lee said.

Police sources said South Korean authorities are likely to declare the highest level of emergency preparedness for a Kim visit.

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Under that plan, all five of Seoul’s 1,200-officer-strong police divisions specializing in crowd control would be mobilized, with all annual leave canceled for police officers, said one police official, who asked not to be named as he was not authorized to speak publicly.

Tens of thousands of other officers would likely be called up from other police and government agencies, including the military, he said.

FREE SPEECH CONCERNS

Some critics of the Moon administration say they fear authorities will work with North Korean security to tamp down even peaceful displays of opposition to Kim.

“If Kim Jong Un really visits Seoul, what the government should never, ever do is contrive a ‘welcoming’ atmosphere by forcibly banning anti-Kim Jong Un protests or mobilizing pro-North Korea gatherings,” said Liberty Korea Party lawmaker Baek Seung-joo. “The Blue House cannot and should not order anything more than sheer maintenance of order when Kim Jong Un visits Seoul.”

Another lawmaker who visited Pyongyang during the September Korean summit told South Korean media Kim Jong Un acknowledged the likelihood of protesters if he visits, but did not seem concerned by the “disagreeing voices” he might face.

A spokesperson for South Korea’s presidential Blue House said Moon’s administration would “strive to actively communicate” with critics of a Kim visit.

“There will be no compromise in our firm stance guaranteeing free speech in the process,” Nam Sang-kyu told Reuters in a statement. “As... the contemplated visit by (Kim) is to mark the very first visit by a North Korean leader, our administration is fully committed to prepare the event in a safe and efficient manner, and thus successfully complete the event.”

During the summit with Trump in Singapore, local police, hotel staff, and North Korean security guards at Kim’s hotel would warn onlooking guests to keep their phones down and forced some who were caught taking photos of Kim to erase them.

“In South Korea, there are bound to be protesters against Kim Jong Un’s dictatorship,” Baek said. “Only when we allow protest and also show Kim Jong Un Seoul, and the way our system is, can there be a learning moment for Kim Jong Un.”