The remarks came amid reports North Korean leader Kim Jong-un's estranged half-brother, Kim Jong-nam, was killed at an airport in Malaysia on Monday after two women allegedly attacked him, possibly with poison.

RFA stopped short of listing the number of women under the bureau's command but stressed the expanded role of female agents.

"There were female agents such as Kim Hyon-hui and Won Jeong-hwa in the past, but their role has been recently expanded,"

the report said. Kim took part in the 1987 bombing of a Korean Air passenger plane heading for Seoul from Baghdad, while Won was arrested in July 2008 after having wheedled military secrets out of a number of senior officers after arriving in South Korea posing as a defector.

Ahn Chan-il, director of the World North Korea Research Center in Seoul, said North Korea has been known to use attractive female agents in assassination attempts with poison needles rather than men who participated in clandestine operations with knives and guns.

Another North Korean defector, who gathers intelligence from China, said female agents who are well dressed and trained have been operating in teams of three to four.

The North Korean bureau is known to select attractive women versed in foreign languages after screening them for their family origin and loyalty to the ruling Workers Party. (Yonhap)