He told Associated Press on today that he received a threatening call saying that "me and Boko Haram are not supposed to exist".
Boko Haram is blamed for more than 360 killings this year alone in Nigeria.
The threats come as Nigeria's government has been trying to find intermediaries to negotiate with the Boko Haram.
However, one man named as a possible go-between said he has abandoned the effort. Salkida suspects security agencies are threatening him.
This is the second mediator to pullout after a respected cleric mediating in peace talks between the Nigerian government and the Islamist sect, Boko Haram announced he was quitting the talks, accusing the government of insincerity.
The Committee to Protect Journalists says they are concerned about Salkida's safety.