A leader of a Sinai-based extremist group says militants have killed soldiers because they serve an apostate army and those who are fighting Islam and killing Muslims.

Abu Osama al-Masri, the leader of Ansar Beit al-Maqdis or Champions of Jerusalem, made the statement in an audio recording released on the group's Twitter account late Friday.

In the recording, al-Masri tells families to pull their sons out of the army and prevent them from joining it.

The recording sounded like previous messages released by al-Masri and corresponded with other Associated Press reporting.

In October, 31 soldiers were killed in the Sinai, the deadliest terror attack on Egypt's army in modern history. There has been no claim of responsibility yet for the attack. Al-Masri's group has claimed a series of other attacks.