Pressure must be kept on North Korea to make it abandon its nuclear and missile development programs, Japanese Foreign Minister Taro Kono said Friday.

Amid a conciliatory mood on the Korean Peninsula following the North's participation in the Pyeongchang Winter Olympics in South Korea, Kono warned against falling for Pyongyang's charm offensive.

North Korea "sees that nuclear weapons are an important means to achieve their goals" including "removing U.S. forces from the Korean Peninsula," he said in a speech delivered at the Munich Security Conference. "This is exactly what we should never accept."

Kono called for strictly implementing U.N. sanctions against North Korea and pointed to suspected evasions by the country of the measures through ship-to-ship transfers of goods at sea.

Japan recently spotted a North Korea-flagged tanker engaging in such activities in the East China Sea and reported it to the United Nations, according to the Foreign Ministry.