The mother of a Japanese journalist believed to have been killed by the masked Islamic State militant known as "Jihadi John" says she wishes to see no more violence, and that her peace-loving son would agree with her.

Junko Ishido, the mother of Kenji Goto, told Japan's NHK public television Friday that she wants to see the world free of conflicts. Goto was seen in an Islamic State-group beheading video in January, apparently with the militant Mohammed Emwazi.

The U.S. says a drone strike targeted a vehicle in Syria believed to be carrying Emwazi.

Japan's Chief Cabinet Secretary Yoshihide Suga says the government is seeking details from Washington, as Japanese authorities continue to investigate the death of Goto and another victim, Haruna Yukawa, in Syria.