They have all taken up isolation for 14 days after returning from training abroad, the federation said in a statement.

World swimming champion Boglárka Kapás and world championship bronze medallist Dominik Kozma confirmed their positive tests earlier in the day.

Kapás said she would have needed two negative tests in order to continue her preparations, but her second test had come out positive. She said she was “feeling perfectly well” and had not noticed any symptoms.

Kapás won bronze in 800 metre freestyle at the Rio Olympics in 2016 and won the 200 metre butterfly at the Gwangju world championships last year.

Kozma, who came third in the men’s 4×100 metre freestyle relay of the 2017 world championships hosted by Hungary and is a four-time European championship bronze medallist, told public news channel M1 that he, too, was asymptomatic.

MTI Photo of Boglárka Kapás: Tamás Kovács