Several major cryptocurrency exchanges warned users this week that transfers involving HTX could face additional compliance checks after the United Kingdom sanctioned the exchange over alleged ties to Russian financial networks.

The U.K. government added HTX to its Russia sanctions list as part of a broader package targeting entities accused of helping sanctions evasion and illicit financial activity linked to Moscow.

British authorities said they had “reasonable grounds to suspect” HTX provided financial services connected to sanctioned entities including crypto exchange Garantex and the A7 network, whose A7 LLC issues the ruble-pegged A7A5 stablecoin.

The Foreign Office said the A7 network had used a Kyrgyz bank and a major…