ISIS-inspired women arrested in NYC for allegedly trying to build bomb

Federal authorities have arrested two women who were allegedly planning to detonate a bomb in the New York City area after being radicalized by ISIS, ABC News has learned.

The public was never in danger, as it was all part of a lengthy undercover FBI operation. The women were allegedly looking to build an improvised explosive device, but it's unclear how far along their plan had reached.

The women -- in their 20s and 30s -- were arrested earlier today in New York, and authorities are convinced ISIS propaganda and their alleged online activities contributed to their ultimate shift toward violence, ABC News was told.

Such arrests tied to ISIS have become a regular occurrence recently.

Last week, two cousins were arrested in Chicago -- one of them a current member of the Illinois National Guard -- for allegedly trying to launch attacks in the U.S. and overseas on behalf of ISIS. They were also nabbed in an FBI undercover operation, and both men had been under FBI surveillance for months, federal authorities said.

The week before, a former U.S. Air Force veteran was indicted by federal authorities for allegedly trying to join ISIS. Tairod Nathan Webster Pugh, 47, who is from New Jersey, had been living overseas for years, was secretly arrested two months ago after being deported back to the United States.

On his laptop, FBI agents allegedly discovered more than 180 jihadist propaganda videos and noticed he had been conducting online searches for such phrases as "borders controlled by Islamic state," "kobani border crossing," and "who controls kobani."

Last month, three New York City men were arrested on charges they allegedly conspired to join ISIS but also expressed willingness to carry out attacks on the terror group's behalf in the United States. The men had planned to travel to the Middle East and had also pledged to launch attacks in this country, including one on President Obama or planting a bomb in Coney Island, Brooklyn, federal officials said.

Over the past 18 months, about 30 people have been charged with joining terrorist groups in Syria and Iraq or trying to do so.