(CNN) Assyrians in northeastern Syria villages awoke Tuesday to ISIS militants at their doors, with the Islamist extremists abducting scores from the Christian group and forcing hundreds more to run for their lives, an advocate said.

The ISIS fighters burst past a few men guarding the village of Tal Shamiram at about 4 a.m. (9 p.m. ET Monday) and abducted children, women and the elderly, said Usama Edward, founder of the Assyrian Human Rights Network.

Talking to CNN from Stockholm, Sweden, Edward said that between 70 and 100 people were kidnapped in that village and others in the same cluster near Tal Tamer.

The Syrian Observatory for Human Rights reported that ISIS had abducted 90 Assyrians. "Reliable sources" told the London-based monitoring organization that they'd overheard ISIS militants talking on wireless devices about having detained "56 crusaders" in Tal Shamiram alone.

In the village of Ghibsh, ISIS executed two citizens for "dealing with the Kurds," the Syrian Observatory reported. Syrian Kurdish fighters -- who are part of the People's Protection Units, or YPGs, and affiliated with Kurdish fighters out of Iraq -- are among those battling the Islamist extremist group.

About 700 Assyrian families managed to escape the onslaught, with 600 taking up refuge in St. Mary's Cathedral in al-Hasakah, Syria, Edward said. The Assyrians lack food, water, blankets and other necessities after years of being in the middle of a civil war.

"They are facing a possible massacre by the (Syrian) regime and by ISIS," Edward said. "Everyone is fighting everyone else. They are surrounded."

Advocate: 'A miracle' Assyrians have survived

ISIS has attacked numerous minority groups during a bloody campaign to create a vast caliphate across Syria and Iraq under its extreme version of Sharia law.

That includes Assyrians in Qaraqosh, a historic town of 50,000 people in northern Iraq about 20 miles southeast of Mosul that was overrun this summer.

Many Mosul residents had fled to Qaraqosh after the Islamist extremists took over that city, Iraq's second-largest. At the time, ISIS issued an ultimatum to Christians living there: Convert to Islam, pay a fine or face "death by sword."

The latest reported abduction occurred about 160 miles (255 kilometers) east of Qaraqosh.

Edward, from the Assyrian Human Rights Network, said members of his group and other Syrian Christians have been "left all alone" by Syria's government and the world. Kurdish fighters may launch an operation to rescue those abducted, "but it very dangerous (and) everyone could get killed."

"This is like a miracle that they have survived this long," he said of his fellow Assyrians. "How can these people stay alive? They are trying to defend their homes."

Violence rages in Iraq, Syria

ISIS isn't the only threat to Assyrians, given all the violence around them in the places they call home.

Nearly four years in, Syria's civil war is still raging -- with a U.N. official in January reporting some 220,000 people killed and 7.6 million displaced. There are atrocities in that war that aren't being blamed on ISIS, including a Human Rights Watch report out Tuesday blaming Syria's government for "hundreds of new discriminate attacks" in the past year, including the use of barrel bombs.

Iraq isn't exactly a picture of stability, either.

The militant group isn't thought to have penetrated Baghdad. That city has seen more than its fair share of attacks in recent months -- the latest being bombings, just a few minutes apart, that killed 21 women, children and men on Tuesday, according to officials.

Still, it's ISIS that has gotten the most traction internationally for its success and tactics.

Pressure growing on ISIS

The militant group has ruthlessly gone after groups that don't give into its subscribe to ISIS' take on Islam. Some of those affected are Christians, but many others are Muslims who don't accept its radical ideology.

But it's received pushback recently, with a strong showing from Kurdish Peshmerga fighters and the retooling of Iraq's once maligned military. There also have been hundreds of U.S.-led airstrikes in Iraq and Syria targeting ISIS, which the U.S. government also refers to as ISIL.

"This is a difficult mission and it will remain difficult for some time," President Barack Obama said this month . "(But) our coalition is on the offensive, ISIL is on the defensive, and ISIL is going to lose."

The threat is anything but over. In some places, the group is holding and even gaining ground.

The biggest test, for all sides, will likely come over Mosul.

Up to 25,000 Iraqi troops could begin their push to retake that northern Iraqi city as soon as April, a U.S. official has said. A U.S. Defense Department official said Washington is supplying the Iraqis with 10,000 M16 rifles, 10,000 M68 close combat optical scopes, some 23,000 ammunition magazines and "thousands" of additional helmets and Kevlar vests in preparation for the Mosul assault.

This shipment is in addition to 250 mine-resistant vehicles sent over in January, and some 1,800 Hellfire missiles shipped over in 2014 and this year.