If North Korea is responsible for the killing of Kim Jong Un's half brother, Kim Jong Nam, then the reclusive country should be relisted to the U.S. terrorism sponsor list, a U.S. congressman told Radio Free Asia (RFA). According to reports, Kim Jong Nam was assassinated in Malaysia by two women believed to be North Korean operatives.

On Thursday, Rep. Ted Poe (R-Texas), who serves as chairman of the House's subcommittee on terrorism and trade, told the U.S. broadcaster that it is a "very serious problem" if Kim Jong Un was behind the killing of his half brother. Poe reportedly said that North Korea's involvement in the murder would be another terrorist act by the country.

Malaysian police has been investigating the killing of Kim Jong Nam, who is suspected to have been poisoned at the country's airport Monday. Several arrests have been made in connection to the murder, including that of two females — one with an Indonesian passport and another with Vietnamese documents. Kim was reportedly poisoned as he prepared to board a flight to his home in Macau on Monday morning. Authorities are yet to release the results of an autopsy that was conducted Wednesday.

Last year, Poe had introduced a similar bill to the previous House, saying Pyongyang meets the criteria for terror sponsor designation. The bill later passed through the Foreign Affairs Committee but did not move forward as the House expired at the end of last year, Yonhap News Agency reported.

North Korea was on the U.S. terrorism sponsor list for the 1987 mid-air bombing of a Korean Airlines flight that killed all 115 people aboard. However, in 2008, the U.S. administration under then-President George W. Bush removed Pyongyang from the list in exchange for progress in denuclearization talks.

Several requests had been put forward to bring North Korea back to the list after it allegedly carried out a cyberattack on Sony Pictures in 2014.