The dead included a police officer, two civilians and the two female suicide bombers, who detonated themselves at around 8 am (0700 GMT) on Sunday in the Galdi neighborhood near the entrance to the town, Reuters reported late Sunday.
"It happened not far from the town stadium when the police officer who was killed attempted to carry out a routine check," said one of the military officers, who asked not to be named as he was not authorized to speak to the press.
He said authorities had dispatched teams to the scene of the bombing to gather more details and it was possible the death toll from the attack could rise.
Mora lies just a few kilometers from Boko Haram's strongholds in northeastern Nigeria.
The extremist group has stepped up its attacks in the area since Cameroon last year launched a crackdown on the group, which had previously used the Extreme North region as a base for recruiting and supplying its operations in Nigeria.
Cameroon is a major contributor to an 8,700-strong, Nigerian-led regional force expected to start operations against Boko Haram this year.