EL-ARISH, Egypt — Suspected Islamic militants gunned down a Coptic Christian inside his home in northern Sinai, the sixth such killing in a month’s time in the restive region, officials said Friday, prompting some Christian families to flee from the area for fear of being targeted next.

The militants stormed the home of Kamel Youssef, a plumber, on Thursday and shot him to death in front of his wife and children in the town of el-Arish, said two officials, speaking on condition of anonymity because they were not authorized to talk to reporters.

No militant group has claimed responsibility for the attack but earlier this week, Egypt’s Islamic State affiliate, which is based in the Sinai Peninsula, vowed in a video to step up attacks against the embattled Christian minority.

A spate of killings by suspected militants has spread fears among the Coptic community in el-Arish as families left their homes after reportedly receiving threats on their cellphones.

A day before Youssef’s killings, militants killed a Coptic Christian man and burned his son alive, then dumped their bodies on a roadside in el-Arish. Three others Christians in Sinai were killed earlier, either in drive-by shootings or with militants storming their homes and shops.

The Coptic Christian Church has made no official comment on the spate of killings.

Coptic Christians, who make up 10 percent of Egypt’s population, have increasingly come under attack since the military’s overthrow of elected Islamist President Mohammed Morsi in 2013. A top target of Islamic extremists throughout the years, the Christians heavily supported the army chief-turned-president, Abdel-Fattah el-Sissi, and his security crackdown on Islamists since Morsi’s removal.

The northern region of Sinai, bordering the Gaza Strip and Israel, has been the battleground between the military and Islamic militants since 2011, when the region sank into lawlessness during the 18-day uprising that led to the ouster of longtime autocratic President Hosni Mubarak.

El-Sissi declared a state of emergency and imposed a curfew in the volatile region in 2014 in the aftermath of deadly suicide bombings that killed over 30 soldiers. Blaming the stepped-up militancy on Gaza’s ruling Hamas group, which uses underground tunnels for smuggling contraband, the Egyptian military razed hundreds of houses in the border area to create a buffer zone and stop what it described as the infiltration of extremists from Gaza.

Since 2013, Islamic militants have carried out several suicide bombings across Egypt, mainly against the police and the army. However, in December, an IS-affiliated suicide bomber blew himself up inside a landmark Cairo church, killing around 30 worshipers, mostly women.

That attack marked a turn in the Sunni militant group’s strategy as Christians became its top targets. The extremists have used Christians’ support for el-Sissi as a pretext to increase attacks against them.

The Islamic State group’s video, released Monday, showed the bomber behind the December church attack and described the Christians as “infidels” who are empowering the West against Muslim nations.