An unlikely an unofficial alliance has formed in Egypt’s Sinai Peninsula in the fight against the Islamic State group, also known as ISIS. The men pushing back the group aren’t police or soldiers, a CNN exclusive Tuesday found, but Bedouin tribesmen who abhor the group's understanding of Islam and fear their rapid spread in the region.

"They are not Muslims," said Sulieman El Meharwel, one of three tribal leaders who CNN spoke with. "They kill anyone who doesn't agree with them. We accept everyone, including Christians and Jews, but we can never accept ISIS." 

The leaders said they managed to hold back the militant group, which maintains a stronghold in Syria and Iraq, without firing a single shot.  They said firing guns would risk starting a tribal war in the Sinai Peninsula.

"We've stopped ISIS more than 20 times. We went out with more than 50 cars and kicked them back," said Hussein Abu Atwey, one of the tribal leaders.

An ISIS-affiliated group in Egypt’s Sinai Peninsula, also called the Sinai Province, has claimed responsibility for bringing down a Russian airplane last week. All 224 people on board were killed in the crash. While authorities continue to investigate the claims, Western officials have increasingly considered ISIS’s claim of responsibility plausible. Many now believe an explosive device was hidden in the plane’s cargo. The group was responsible for a string of deadly attacks in the Sinai Peninsula in July, killing as many as 70 people. Militants in Iraq released a video showing fighters handing out candy and brandishing smiles in celebration of the attacks. 

"ISIS is scared because we are united. They were scared of us. If we didn't wear our guns, they wouldn't be afraid. We had enough guns and we forced them back," Abu Atwey said. "The army told us, 'Everyone get your gun out if they try to come into your area.' "

But the Egyptian government has long been suspicious of Bedouin tribes, and the nomads said many of their tribesmen feel reluctant to support the government. When they carry weapons, they risk being mistaken for militants, the leaders said.  

"The tribes could defeat ISIS. If the government came and gave us arms and said fight ISIS, they would fight ISIS," said Abu Atwey. "They'd finish them completely."