Kuwaiti official Al-Musallam was elected to succeed Julio Maglione as head of FINA in June last year, with this his first World Championships as President.

However, Hungary's capital Budapest was only awarded hosting rights in February of this year, after the original host city of Fukuoka in Japan was forced to postpone its edition until 2023 due to the COVID-19 pandemic.

The FINA World Championships are returning to Budapest for the second time in three editions, with the city having also held the event in 2017.

In his address at the Opening Ceremony, Al-Musallam thanked Hungarian organisers for ensuring that a World Championships could be held this year, in addition to the 2023 edition in Fukuoka and 2024 edition in Doha.

"Many of us here will have many happy memories from our time in Budapest five years ago," Al-Musallam reflected.

"Of course we did not anticipate that we would be back in your capital city again with another World Championships so soon, but the COVID-19 pandemic has led to many unexpected outcomes.

"I am so grateful to everybody who has worked so hard to organise this event at such short notice.

"Normally there are years of planning ahead of hosting a World Championships.

"You have delivered this with only several months' notice.

"It is because of Hungary’s kind offer to step in, and host these Championships that our athletes have been given the opportunity to compete, after it had looked likely that there would not be a World Championships this summer.

"I know that the athletes will want to join me in giving you a very big thank you."

The FINA President also commended athletes for their "resilience" shown in "such challenging circumstances" of the pandemic, and said he is looking forward to sporting competition across five aquatics disciplines in Budapest which is due to run until July 3.

"I am sure that you are all as excited as me to watch what I know will be some very memorable aquatics sport here over the coming days," he commented.

"The venues are perfect.

"Budapest is an exceptional host city.

"Everything is ready for the athletes to showcase their talents to the world."

After Al-Musallam's speech at the Opening Ceremony, Katalin Novák, who took office as Hungarian President last month, officially declared the FINA World Championships open.

The Opening Ceremony was followed by the first five swimming finals at the World Championships.

International Olympic Committee President Thomas Bach was also in attendance, and presented the medals as part of the victory ceremony for the men's 400 metres freestyle, won by Australia's Elijah Winnington.

Bach is due to address the FINA Extraordinary Congress in Budapest tomorrow.

A report from the FINA Transgender Taskforce is another of the significant items on the agenda, as well as elections to the newly-formed Aquatics Integrity Unit.