Eye on ISIS: 150 held in Syria; 3 arrested in U.S. in alleged plot

(CNN)A war that defies conventional borders requires a bird's-eye view to better grasp the various shapes that the battle with ISIS is taking.

Almost daily, there are gains and losses of territory by ISIS in Iraq and Syria, and reports of terror cells operating in Europe and plotting attacks on the West.
Here are some of the latest headlines:

Activist: Lives of 150 Christian hostages in danger

    ISIS is holding 150 Assyrian Christians as hostages in Syria, and will threaten to kill them, says Osama Edward, founder of the Assyrian Human Rights Network.
    Edward says ISIS has taken over some 35 Assyrian villages, forcing thousands of families to flee.
    ISIS reportedly abducts 150 Christians in Syria
    newday sot robertson isis abducts christians syria_00001418

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    His organization put out the new estimate of Assyrian Christian hostages on Wednesday, and said ISIS is expected to release a message threatening to kill them.
    The Assyrians were kidnapped early Monday from villages near Tal Tamer in northeastern Syria.
    Edward said he feared the hostages would face the same fate as Assyrians targeted in Iraq and the more than 20 members of Egypt's Coptic Christian minority slaughtered by ISIS in Libya last month.
    "They are facing death. People are unarmed, they are peaceful. And they need help. They are just left alone -- no one's protecting them," he said.

    Alleged plotters discussed hijacking plane

    The FBI has arrested three men who allegedly attempted to fly from New York to Turkey in hopes of eventually joining ISIS in Syria.
    One of the three men said the plan was to travel on Wednesday, hijack a flight and divert it "to the Islamic State, so that the Islamic State would gain a plane," according to a New York federal court complaint released in Brooklyn.
    In addition, the complaint said, one of three men arrested spoke of shooting U.S. President Barack Obama.
    The suspects -- identified as Abdurasul Jaraboev, 24; Akhror Saidakhmetov, 19; and Abror Habibov, 30 -- face charges that include providing material support for terrorists, authorities said.
    Jaraboev allegedly posted online: "Is it possible to commit ourselves as dedicated martyrs anyway while here? What I'm saying is, to shoot Obama and then get shot ourselves, will it do?"
    The men allegedly discussed staging attacks in the United States, according to court papers.
    Parts of their plan for attacks were posted online, the documents said.

    Kurds: Tide is turning in fight against ISIS

    From CNN's Ben Wedeman:
    Peshmerga: ISIS 'can't overcome us'
    Peshmerga: ISIS 'can't overcome us'

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    The dilemma over when to strike Mosul

    CNN's Barbara Starr reports:
    While U.S. Central Command officials sketched a likely April or May time frame for a looming battle against ISIS in Mosul last week, other military officials say there are alternative strategies that involve a series of strikes in other locations before an all-out attack on Mosul.
    At the same time, new Defense Secretary Ash Carter is making it clear he will not commit quickly to a timetable, and wants assurances the Iraqi military is up to the task, a senior U.S. military official said.
    Carter wants to ensure military action is not ordered without strong indications Iraqi forces will be successful.
    "If we begin this, and it doesn't work, it will be very bad," the official said of an effort to retake Mosul. "The secretary doesn't want it to go faster than the Iraqis are ready to go."

    What is ISIS' appeal for young people?

    Experts tackle this question, and conclude there are a number of reasons why youth are being attracted to ISIS.
    ISIS recruiting kids to be 'cubs of the caliphate'
    ISIS recruiting kids to be 'cubs of the caliphate'

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    Children and young people feature in the terrorist group's propaganda, including a recent video showing boys in camouflage and ISIS bandanas learning hand-to-hand combat. The militants call them their "Cubs of the Caliphate."
    Experts say ISIS has especially ramped up its efforts to lure young women -- seen as potential brides for its fighters -- into the territory under its brutal control in Syria and Iraq.
    The key points:
    -- ISIS runs a powerful propaganda machine on social media
    -- ISIS promises the good life
    -- ISIS has a diffuse but efficient recruiting network
    -- ISIS is outwitting Western governments' efforts