WASHINGTON (NewsNation Now) — Despite years of military targeting by the U.S.-led coalition, the group known as Islamic State Khorasan, or ISIS-K, has survived to launch a massive new assault as the United States and other NATO partners withdraw from Afghanistan and as the Taliban return to power.

The attack claimed the lives of at least 60 Afghans and 13 U.S. service people, with at least 143 Afghans injured. ISIS-K has fought recently with the Taliban, and the two groups are considered bitter enemies that feed off each other as they compete for influence in the region.

Experts say the group, which takes its name from the Khorasan Province, a region that covered much of Afghanistan, Iran and Central Asia in the Middle Ages, has the capability to carry out similar attacks in the region.

“What we’re seeing in Kabul today,” former National Security Advisor H.R. McMaster said, “is only the beginning of what will be, I think, a series of terrorist attacks that will inflict tremendous human suffering on the Afghans initially, … then to others in the region.”

ISIS-K started as several hundred Pakistani Taliban fighters who took refuge across the border in Afghanistan after military operations drove them out of their home country. Other, like-minded extremists joined them there, including disgruntled Afghan Taliban fighters unhappy with what they saw as the Taliban’s overly moderate and peaceful ways.

As the Taliban pursued peace talks with the United States in recent years, discontented Taliban increasingly moved to the more extremist Islamic State, swelling its numbers. Most were frustrated that the Taliban was pursuing negotiations with the U.S. at a time when they thought the movement was on the march to a military win.

The group also has attracted a significant cadre from the Islamic Movement of Uzbekistan, from a neighboring country; fighters from Iran’s only Sunni Muslim majority province; and members of the Turkistan Islamic Party comprising Uighurs from China’s northeast.

Many were attracted to the Islamic State’s violent and extreme ideology, including promises of a caliphate to unite the Islamic world, a goal never espoused by the Taliban.

While the Taliban have confined their struggle to Afghanistan, the Islamic State group in Afghanistan and Pakistan has embraced the Islamic State’s call for a worldwide jihad against non-Muslims.

The Center for International and Strategic Studies counts dozens of attacks that Islamic State fighters have launched against civilians in Afghanistan and Pakistan, including minority Shiite Muslims, as well as hundreds of clashes with Afghan, Pakistani and U.S.-led coalition forces since January 2017. Though the group has yet to conduct attacks against the U.S. homeland, the U.S. government believes it represents a chronic threat to U.S. and allied interests in South and Central Asia.

They are enemies. While intelligence officials believe al-Qaida fighters are integrated among the Taliban, the Taliban, by contrast, have waged major, coordinated offensives against the Islamic State group in Afghanistan. Taliban insurgents at times joined with both the U.S. and U.S.-backed Afghan government forces to rout the Islamic State from parts of Afghanistan’s northeast.

A U.S. Defense Department official, speaking to The Associated Press on condition of anonymity because he was working covertly, said previously that the Trump administration had sought its 2020 withdrawal deal with the Taliban partly in hopes of joining forces with them against the Islamic State affiliate. The administration saw that group as the real threat to the American homeland.

Military officials, however, say they remain vigilant regarding the perpetrators of Thursday’s attack.

“We’ve been clear all along that we retain the right to operate against ISIS in Afghanistan,” Gen. Kenneth McKenzie, head of U.S. Central Command, said. “And we are working very hard right now to determine attribution to determine who’s associated with this cowardly attack. And we’re prepared to take action against them. 24/7, we are looking for them.”