Kim Jong Nam, left, exiled half-brother of North Korea's leader, in Narita, Japan, on May 4, 2001, and North Korean leader Kim Jong Un on May 9, 2016, in Pyongyang, North Korea.

KUALA LUMPUR, Malaysia — North Koreans working overseas were told Saturday by North Korean authorities not to watch reports on the murder of Kim Jong Nam, the half brother of North Korean leader Kim Jong Un, sources close to North Korea in Southeast Asia and other places told The Yomiuri Shimbun.

North Koreans overseas involved in trade and other businesses were issued a gag order immediately after the 45-year-old half brother was assassinated in Kuala Lumpur last month, according to sources, suggesting that Kim Jong Un's administration has been extremely alert for any information of the murder flowing into the country.

Kim Jong Nam inherited the so-called "bloodline of Mt. Paektu," which refers to the descendants of North Korean founder Kim Il Sung. It is believed that issuing the order not to watch reports on the murder is aimed at preventing damage to Kim Jong Un's character when it becomes known that he ordered the assassination.

North Korea claimed the murdered person was identified as "Kim Chol with a diplomatic passport."

North Koreans related to trade and other businesses said they were notified of the order by secret police officers and State Security Ministry officials on Saturday morning.

North Korean authorities recently prohibited diplomats, dispatched workers and others living overseas from connecting to the internet using their mobile phones, according to U.S.-funded Radio Free Asia.