Palermo Open tournament organisers have been left "embittered" and "profoundly disappointed" over Simona Halep's decision to withdraw from the event.

Halep on Sunday cited the rise in coronavirus cases in Romania and anxieties around international air travel as her reasons for opting out of the first WTA Tour event since March.

The Romanian's participation in the tournament, which starts on August 3, was in doubt due to new quarantine regulations in Italy.

It was announced on Friday that all visitors who have spent time in Romania or Bulgaria in the past 14 days would need to quarantine for two weeks upon arrival in Italy.

Tournament director Oliviero Palma wrote to Italy's health minister Roberto Speranza to seek an exemption for Halep, and regional assessor of health Ruggero Razza informed the 2019 Wimbledon champion that tennis players would not need to quarantine.

Yet the two-time grand slam champion has delayed her return as she is not ready to head overseas.

She said in a statement released to Stats Perform News on Sunday: "Given the recent rise in COVID-19 cases in Romania and my anxieties around international air travel at this time, I have made the tough decision to withdraw from Palermo.

"I want to thank the tournament director and the Italian ministry of health for all their efforts on my behalf and I wish the tournament a successful week."

Palma was not at all impressed with Halep's withdrawal.

He said: "We found out Halep's decision with great bitterness. Yesterday we were optimistic, and we had informed Halep's staff about the fact that professional players are not obliged to quarantine.

"Nevertheless, Halep's staff only communicated us the final decision, frustrating all our efforts. We are embittered and profoundly disappointed."