An Idaho 18-year-old was arrested after he allegedly made plans to carry out attacks targeting local churches in the name of ISIS, the U.S. Department of Justice said.

Alexander Scott Mercurio, who pledged his allegiance to ISIS, was charged with “attempting to provide material support or resources to a designated foreign terrorist organization,” according to the Justice Department.

In Loyob, they do not believe anyone from their village was capable of taking part in the jihadist massacre at Moscow's Crocus City Hall.

But Faridun Shamsiddin is now one of four Tajik citizens held in a Moscow jail suspected of murdering at least 143 people last week. The 25-year-old is also accused of recruiting two other men to help the gunmen.

He left Loyob, about 40km north-west of the capital Dushanbe, several months ago in search of work in Russia.

The four men suspected of carrying out a brutal attack at a Moscow concert hall that killed at least 139 people have appeared in court on terror charges, as the Kremlin defended its security services criticized for failing to prevent the massacre.

Three of the suspects were bent double as they were marched into the Moscow courtroom late on Sunday night, while the fourth was in a wheelchair and appeared unresponsive.

The U.S. has intelligence confirming Islamic State's claim of responsibility for a deadly shooting attack at a concert near Moscow on Friday, a U.S. official told Reuters.

Here is information about the Islamic State's Afghan branch known as ISIS-K and their motives for attacking Russia:

WHAT IS ISIS-K?

Islamic State Khorasan (ISIS-K), named after an old term for the region that included parts of Iran, Turkmenistan and Afghanistan, emerged in eastern Afghanistan in late 2014 and quickly established a reputation for extreme brutality.

As the world absorbs the horror of the ISIS-K slaughter inside a Russian concert hall, prominent members of Congress are warning the Afghan-based terror group could strike inside the United States.

House Foreign Affairs Committee Chairman Mike McCaul said Sunday the threat of an attack was heightened by President Joe Biden‘s bungled withdrawal from Afghanistan, which gave ISIS-K  a breeding ground to train and carry out attacks.

Five years ago this month, an American-backed Kurdish and Arab militia ousted Islamic State fighters from a village in eastern Syria, the group’s last sliver of territory.

Since then, the organization that once staked out a self-proclaimed caliphate across Iraq and Syria has metastasized into a more traditional terrorist group — a clandestine network of cells from West Africa to Southeast Asia engaged in guerrilla attacks, bombings and targeted assassinations.

At least 133 people were killed and more than 145 were injured on Friday in an attack after a group of armed individuals opened fire at the Crocus City Hall music venue near Moscow, Russian state media agency TASS reported, citing the Russian Investigative Committee.

The number of reported casualties would make this one of the deadliest attacks near Russia's capital in recent years.

Here's what we know so far:

There are always questions after any attack as to why it was not stopped or detected. But the Moscow attack raises particularly difficult issues for Vladimir Putin at a time of international tension and mistrust. And much of that comes because of a warning from Washington.

The 7 March warning from the US to its own citizens was unusually specific. It talked of reports that "extremists" had "imminent plans to target large gatherings in Moscow" and specifically mentioned concerts. It advised Americans in the city to avoid large gatherings over the coming 48 hours.