(Reuters) - The United States on Friday added 105 Russian and Chinese firms to a trade restriction list over their alleged support of the Russian military as Washington seeks to keep up pressure on Moscow's war effort in Ukraine.

The companies -- 63 Russian and 42 Chinese as well as 18 from other countries -- were targeted for a host reasons, from sending U.S. electronics to Russian military-related parties to producing thousands of Shahed-136 drones for Russia to use in Ukraine.

Being added to the entity list forces U.S. suppliers to get a difficult-to-obtain license before shipping to the targeted companies. Many of the firms added to the list on Friday were given a special designation that also forces overseas suppliers to get the same U.S. licenses before shipping to the targeted companies.

The moves show the Biden administration is trying to keep up pressure on the companies sustaining Moscow's war in Ukraine despite a raft of Western sanctions aimed at hobbling that effort and amid reports that restricted American technology is still reaching Russia's defense industry.