The 28-year-old American, the gold medallist at Tokyo 2020, won the women's foil event at the International Fair in the Bulgarian city with the row over Russian and Belarusian participation still simmering in the background.

Kiefer, the world number one, also triumphed at the Busan Grand Prix in March so has now won two FIE events in a row.

She defeated the reigning world champion, Guadeloupe-born Ysaora Thibus of France, 15-11 in a heavyweight final in Plovdiv.

Bronze medals went to Flóra Pásztor of Hungary and Morgane Patru, also of France.

There was success for the French, who are preparing for a home Olympics, as Thibus, Patru, Pauline Ranvier and Anita Blaze joined forces to win the team event thanks to a 45-41 victory over Italy in the final.

The United States won the bronze medals.

In the men's foil World Cup in Acapulco in Mexico, Mohamed Hamza of Egypt won gold at the Palacio Mundo Imperial. 

He claimed a 15-10 victory over Tokyo 2020 Olympic gold medallist Cheung Ka Long of Hong Kong in the final.

Gerek Meinhardt of the US, Kiefer's husband, was one of the bronze medallists to complete a good spell for the married couple.

Italy's world silver medallist Tommaso Marini also made the podium, but reigning world champion Enzo Lefort of France exited in the quarter-finals to Cheung.

The team event went to the US as Meinhardt, Miles Chamley-Watson, Alexander Massialas and Nick Itkin beat Italy 45-41.

France took home the bronze medals.

The start of fencing's qualification window for Paris 2024 has been embroiled in controversy after the FIE allowed athletes from Russia and Belarus to return, following the invasion of Ukraine.

World Cups in Bonn and Tauberbischofsheim in Germany, Poznań in Poland and Saint-Maur-des-Fossés in France have all been cancelled after the host nations all refused to accept the decision.

All of the events were due to be part of the Paris 2024 qualification process.