An overseas tip about an imminent bombing of the Metro Red Line’s Universal City station has forced federal and local law enforcement in Los Angeles to swiftly ramp up security across its sprawling transit system, authorities said Monday.

An anonymous man warned of a potential attack on Tuesday and provided the information on a tip line abroad, according to Deidre Fike, the assistant director in charge of the FBI's office in Los Angeles.

In a series of attacks on "precisely chosen targets," nine Islamic State militants wrought devastation in Paris on Nov. 13, 2015, killing at least 130 people.

A year later, the world is still grappling with violence exported from Iraq and Syria and carried out by those influenced by the missive to build an Islamic caliphate, even as the group's footprint shrinks.

How did Europe get to this point? And why is it so hard for authorities to stop it? This is a look back at The Post's reporting on a year of attacks, and an attempt to explain how we got there.

How would emergency management and public health officials handle a catastrophe that taxed local supplies of vaccines or medical equipment? Since 1999, the federal government has had a way to help: the Strategic National Stockpile.

The stockpile consists of warehouses that contain medicines — both those that prevent the onset of an illness and those that can treat illnesses — and medical supplies and equipment. It is not meant to be the first line of defense, but rather to supplement resources when state and local supplies run short.

A firefighter who responded to a report of a gas leak Tuesday morning was killed in a house explosion shortly after authorities discovered what appeared to be a drug lab.

The Fire Department of New York confirmed the firefighter's death shortly after the Bronx explosion.

The mayor's office had tweeted that the mayor and fire commissioner were at the hospital.