Wimbledon remains concerned Russian and Belarusian leaders might look to use success of their nations' players in this year's championship as propaganda.
Russian and Belarusians can compete at Wimbledon after the All England Club (AELTC) reversed last year's ban.
They must sign declarations indicating their neutrality before entering.
"The neutrality declarations are focused on trying to reduce that as much as possible," said Wimbledon chief executive Sally Bolton.
Ukraine foreign minister Dmytro Kuleba has described the U-turn by Wimbledon as "immoral" and called on the UK government to deny visas for Russian and Belarusian players.