Budapest (AFP) - The Hungarian capital Budapest on Friday marked the anniversary of one its worst-ever shipping disasters, the sinking of a sightseeing vessel on the Danube which killed at least 27 people, mostly South Korean tourists.

The Mermaid sightseeing boat carrying a tour group sank seconds after colliding with the bigger Swiss-registered Viking Sigyn river cruise vessel on May 29 2019.

The body of a 28th victim was never found.

The Panorama Deck company that operated the Mermaid organised a commemorative event on Friday morning involving three boats sailing down the Danube in formation and a wreath being solemnly lowered into the waters under overcast skies.

The bell of one of the boats rang 28 times and the same number of candles was lit on board another of the vessels.

A Panorama Deck spokesman said "the disaster happened because the rules were not kept," referring to regulations governing river traffic on the Danube.

Later on Friday morning, another ceremony took place on the riverbank with a wreath being laid by Budapest Mayor Gergely Karacsony, Foreign Minister Peter Szijjarto and South Korean ambassador Kyoo Sik Choe. 

Karacsony promised that city authorities "will do everything to ensure that such accidents can not happen again".

"A review of rules regulating boat traffic  on the river is underway," he said, adding: "We can look for justice in the unjust".

Captain on trial

The three men announced that a joint monument -- a memorial stone designed jointly by Hungarian and South Korean artists -- would be erected near the scene.

Construction of the monument has been delayed by the novel coronavirus pandemic and is expected to be completed by the end of the year.

The disaster, on a busy stretch of the Danube in the heart of Budapest, was Hungary's worst boating accident in more than half a century.

Some of the victims' bodies were recovered dozens of kilometres (miles) south of the Hungarian capital in the aftermath of the disaster.

Earlier this year, the trial began of the Ukrainian captain of the larger Viking Sigyn vessel.

Yurij Caplinskij, 64, is charged with "endangering waterborne traffic resulting in multiple deaths" and 35 counts of failing to provide help.

During the opening hearing at a district court in Budapest, prosecutors said they were seeking a nine-year jail term for Caplinskij if he admitted all the charges.

The Ukrainian refused to however, and declined to make any further statement.