Ansar Bayt al-Maqdis, a violent Egyptian militant group, announced Monday its allegiance to the Islamic State, making them the first international extremist group to join forces with ISIS, reports David Kirkpatrick, The New York Times' Cairo bureau chief.

"The big fear is that Ansar Bayt al-Maqdis will start acting more like ISIS," Kirkpatrick says. "ISIS is famous for its indiscriminate violence and its truly careless, gratuitous mass killing of civilians."

In a 10-minute audio message on Monday, the Sinai-based militant group allegedly announced its allegiance to ISIS, blaming tyrants and their Jewish allies for decades of Muslim suffering, and calling ISIS "the emergence of a new dawn."

The endorsement means a great deal considering the rivalry between the Islamic State and Egyptian-rooted Al Qaeda, and could now help ISIS recruit fighters and allies in Egypt and beyond, according to the New York Times.

The Islamic State could also share resources with Ansar Bayt al-Maqdis, such as weapons, jihad worldwide prestige, and stolen money and oil, which could revitalize the Egyptian group's insurgency.

Ansar Bayt al-Maqdis has been able to recruit experienced fighters and conduct sophisticated raids from the Western desert to the Sinai Peninsula. The members have touted themselves as protectors of people in the Sinai Peninsula and their attacks have targeted Egyptian soldiers and police officers, resulting in hundreds of deaths. The group has also beheaded informants and killed an American during a carjacking, according to intelligence reports.

The Egyptian government has responded to the militant group's announcement by sending its military to evacuate over 1,100 families from the northern part of the Sinai and near the Gaza border, and establishing checkpoints.

Kirkpatrick worries the government's efforts could backfire. "If it turns out the checkpoints aren't as effective as the government thinks they are, then you've got to think about the possibility that eradicating these homes, this kind of heavy-handed, brute force approach ... might actually radicalize more young people," he said.

"If there are three young people in each home, you guarantee that two of them would turn into Ansar Beit al-Maqdis militants," Abdel Rahim Ali, an analyst affiliated with Egyptian intelligence services, told the New York Times.

Ansar Bayt al-Maqdis was proclaimed a terrorist organization by the United Kingdom government on April 7 and by the U.S. State Department on April 9.