Ukraine -- February 17, 2022

Link here. 

Two RC-135s -- River Joint -- flying along northern border of Ukraine between Kiev and Lviv. Both are apparently RAF a/c. Call signs RRR7214 and RRR6817.

It also appears that a Global Hawk has just entered Ukrainian airspace from the south, the call sign 23155 is an "invalid" call sign and no a/c is identified, but it's flying at an altitude of 51,000 feet -- the only a/c currently in this theater at that altitude is the Global Hawk. This one would be from NAS Sigonella. Later, 11:27 a.m. CT, that "23155" call sign has been replaced with "XCCRM," also a bogus call sign.

Transponders of all four aircraft have now "disappeared" -- 9:59 a.m. CT, February 17, 2022.