The following prefixes were assigned to USSR Arctic islands in late 1989:

4K2 - Franz Josef Land

4K3 - European islands

4K4 - Asiatic islands

DXNS #1382, dated 1989-09-06, reports: 

"QRZDX reports that callsigns of Franz Josef land stations may be changed very soon. Possible new prefixes are 4K3 or 4K5". 

DXNS #1386, dated 1989-10-11 reports:

"The following prefixes are reported to have been allocated: 4K2 Franz Josef Land; 4K3 Soviet European Islands; 4K4 Soviet Asiatic islands."

Club Log maps these prefixes starting 1989-10-01.