Zaslon, also known as “Barrier or Screen,” is one of Russia’s most secretive special-purpose units under the Sluzhba Vneshney Razvedki (SVR), akin to the CIA or MI6 of the U.S. and UK, respectively. Established in the late ’90s, its main responsibilities include protecting Russian diplomats abroad, conducting hostage rescue missions, and securing sensitive documents. Though largely unpublicized, Zaslon’s operations have been observed in various regions such as Syria, Iraq, and Afghanistan.
  

Key Points: 

1. Zaslon is comparable to the CIA’s Global Response Staff, tasked with high-security details and special operations, making it a pivotal unit within the Russian external security service.
2. The unit’s main responsibilities encompass armed protection of Russian diplomatic missions in hostile regions, protecting high-ranking officials during foreign visits, hostage rescue missions, and safeguarding SVR employees during intelligence work.
3. Despite its secretive nature, glimpses into Zaslon’s operations have surfaced, such as a documentary in 2018 that showcased SVR operators training and the involvement in various regions like Syria and Iraq.
4. Zaslon has been pivotal during various diplomatic tensions, such as the assassination of the Russian ambassador to Turkey in 2016, and has been observed during the retreat of Western powers in Afghanistan in 2021.
5. While the existence of Zaslon is often denied or kept under wraps by Russian officials, open-source reporting and modern technology like smartphones have revealed glimpses of its operations, structure, and equipment.

Source: https://greydynamics.com/zaslon-russias-most-secretive-unit/