Four of the missing were Nigerian, while the other 2 were foreigners, reported the Nigerian daily newspaper P.M. News, Lagos.
"There was an attack on the Setraco construction company site in Jama'are town (in Bauchi State) by unknown gunmen, Police Chief Mohammed Ladan said of the Saturday incident. Six company staff, including two expatriates, have been identified as the victims, he said.
Further details were not immediately available.
Celebrity Families of 2014 [PHOTOS]