The terror threat from Afghanistan is intensifying as jihadis in the war-torn nation are the "most capable" of plotting atrocities, US intelligence has revealed.

ISIS is no longer capable of holding ground in Iraq or Syria due to intensive Western military campaigns.

But intelligence analysts have warned the death cult "has sought to gain momentum" and now relies on its "most capable branches".

The deadliest jihadi group is "ISIS-K", which has "expanding capability beyond South Asia" and is plotting attacks in Europe and the US.

Britons are travelling to join terrorist groups around the World, including ISIS-K (ISKP) in Afghanistan.

America’s intelligence services said, in a joint assessment sent to the US Senate: “ISIS-K in South Asia is the group’s branch most capable of carrying out external terrorist attacks and maintains the intent to conduct attacks in South and Central Asia, and globally, although its capabilities vary.

“ISIS-K’s mass casualty attacks in Russia and Iran in 2024, as well as arrests of ISIS-K supporters in Europe and the United States, highlight the group’s expanding capability beyond South Asia and ability to inspire individuals to conduct attacks abroad.”

American intelligence analysts added: “ISIS has suffered major setbacks and is incapable of holding ground in Iraq and Syria.

“In recent years, ISIS saw the U.S. defeat of its physical caliphate in 2019, the loss of three overall leaders in 2022, 2023, and 2025, and renewed counterterrorism efforts this year removing leaders driving global operations.

“Nevertheless, ISIS remains the world’s largest Islamic terrorist organization, has sought to gain momentum from high-profile attacks, and continues to rely on its most capable branches and globally dispersed leadership to weather degradation.”

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.

The U.S. intercepted communications confirming the group carried out twin bombings in Iran that killed nearly 100 people.

In September 2022, ISIS-K militants claimed responsibility for a deadly suicide bombing at the Russian embassy in Kabul.

The group was also responsible for an attack on Kabul's international airport in 2021 that killed 13 U.S. troops and scores of civilians during the chaotic U.S. evacuation from the country.