World number two Iga Swiatek is receiving additional security at the Miami Open after she was harassed by a spectator during her practice.
The issue comes after British player Emma Raducanu was targeted by a stalker during last month's Dubai Open.
Media reports said that Swiatek was verbally harassed by a spectator, who has a history of online attacks against the player, during practice on Sunday.
"Security is a top priority. We monitor the network to catch these types of issues. Constructive criticism is one thing, and threats, hate speech or even disturbance during training is another - this cannot be condoned," a spokesperson for Swiatek told AFP.