Rhee Keun, a former Navy special warfare officer who gained popularity as one of the trainers in the YouTube series “Fake Men,” on Sunday claimed that he has left the country to fight as a volunteer soldier in the war in Ukraine.

The Navy SEAL-turned-YouTuber, also known as Ken Rhee, posted on Instagram photos that appear to be taken at an airport, with the caption, “When the Ukrainian president called for help from all over the world, ROKSEAL (Rhee Keun’s YouTube channel) immediately prepared for a volunteer mission.”

“We established plans, coordinated, and prepared equipment within 48 hours. At first, we planned on leaving the country through official process, but I felt a strong opposition from the Korean government and there was friction,” he said. “We were threatened that we could be treated as a criminal if we enter a travel-banned country.”

He added that his team could not give up on the mission, even if they faced punishment, as they have the skills, knowledge and expertise to help Ukraine.

Rhee said he will assume all subsequent responsibilities in the future.

“I selected my team members, and if I survive, then I will take responsibility for everything and be punished,” he said. “I’ll see you in Korea after the mission is over.”

Following Rhee’s posting, the Ministry of Foreign Affairs on Monday released a statement regarding volunteer soldiers.

The statement warned that, under the current law, Korean citizens who participate in the war as volunteers may be subject to legal punishment.

“Regarding recent Ukraine situation, to protect the lives and safety of citizens, as of Feb. 13, the government has issued a Level 4 travel warning throughout Ukraine and has banned Korean citizens from traveling to (and or visiting) Ukraine,” the ministry said in a statement.

Those who violate the law and enter Ukraine without authorization may be subject to one year in prison or a fine of up to 10 million won ($8,150), the statement added. They also will be ordered to return their current passport and may have difficulties when applying for a passport in the future.

“Be aware that Ukraine is currently going through a war, and we ask again not to enter Ukraine, a country under a travel ban, without permission,” the statement read.