U.S. Withdrawal from Afghanistan: A Critical Analysis of the Immediate Post-2021 Period and Its Security Ramifications for the Region, with a Focus on Iran

The U.S. withdrawal led to the Islamic Emirate of Afghanistan’s (IEA) swift takeover, intensifying concerns of regional instability. Specifically, it raised fears of increased violence within and beyond Afghanistan and heightened threats of cross-border militant infiltrations. Neighbouring Iran, already facing armed opposition, terrorism, religious radicalisation, and the risk of refugee influxes, was especially impacted. Iran’s eastern provinces, notably Sistan and Baluchistan, suffer from economic marginalisation, ethnic identity issues, and separatist tendencies, making them vulnerable to militant infiltration and attacks, further threatening internal security and socio-economic stability. Addressing these layered security challenges requires coordinated regional collaboration and strengthened counter-terrorism strategies. Diplomatic engagement, conflict resolution, and targeted counter-radicalisation programs—all leveraging regional platforms—are needed to counter groups like Islamic State of Khorasan (ISIS-K). Finally, international humanitarian aid, development projects, and inclusive political dialogue within and with Afghanistan are crucial for long-term peace. This paper critically examines the immediate aftermath of the U.S. withdrawal, exploring the international community’s uncertainty about the IEA’s capacity to manage Afghanistan’s security.