(CNN) – The attack that killed 14 people in San Bernardino, California, in December 2015 marked the deadliest terrorist attack on U.S. soil since September 11, 2001.

It also underscored an unsettling reality: ISIS has morphed from a scourge affecting Iraq and Syria to a threat to people around the world.

Since declaring its caliphate in June 2014, the self-proclaimed Islamic State has conducted or inspired over 60 terrorist attacks in 20 countries other than Iraq and Syria, where its carnage has taken a much deadlier toll; those attacks outside Iraq and Syria have killed at least 1,160 people and injured more than 1,700 others.

One San Bernardino killer pledged allegiance to the ISIS leader, investigators say. And ISIS hailed the attackers as “martyrs” and “supporters.”

Did ISIS actually order the attack? Did its ideology inspire the killers?

It can be difficult to divine the precise role that international terrorists play in this or that attack. The person who killed four U.S. Marines and a sailor in Chattanooga, Tennessee, in July 2015, for example, was “motivated by foreign terrorist organization propaganda,” FBI Director James Comey says, though he added that it’s hard to say which terrorist group motivated the killer.

Yet one thing is clear: The deadly tentacles of ISIS have spread quickly, from the terrorist group’s epicenter in Iraq and Syria to points around the globe.

Here’s a look at terrorist attacks outside Iraq and Syria believed to have been inspired or conducted by ISIS or its regional affiliates, along with context about the known connections to ISIS: