WASHINGTON, Oct 2 (Reuters) - U.S. prosecutors on Saturday said they charged a Saudi-born Canadian man for aiding the Islamic State militant group, alleging he tossed grenades in battle and worked with propagandists who publicized the beheading of hostages including U.S. journalist James Foley. The Department of Justice described the man, identified as Mohammed Khalifa, as a "leading figure" in the English-language media unit of the Islamic State in Iraq and Syria, also known as ISIS. The department said Khalifa narrated English-language recruitment videos and was a battlefield fighter before he was captured in 2019 by the U.S.-backed Syrian Democratic Forces, a militia group that controls parts of Syria. He was recently arrested by the Federal Bureau of Investigation and on Saturday, charges against him were unsealed in the U.S. District Court for the Eastern District of Virginia. Islamic State gained global notoriety after releasing videos in 2014 of the beheading of U.S. journalists Foley and Steven Sotloff, and of British aid workers Alan Henning and David Haines. U.S. prosecutors allege Khalifa worked in the unit that publicized the videos. If convicted, Khalifa faces up to life in prison.