The campaign was launched to celebrate the 100^th anniversary of Zátopek’s birth in 1922.

The initiative also coincided with the 70^th anniversary of the 1952 Summer Olympics in Helsinki.

Zátopek won three Olympic titles at the Games in Finland’s capital city, triumphing in the 5,000 metres, 10,000m and marathon events.

No athlete has won all three of the long-distance races at the same Games since.

Zátopek had also won the 10,000m title at London 1948, along with securing silver in the 5,000m.

Zátopek was the first athlete from the former Czechoslovakia to be awarded the Pierre de Coubertin prize by the International Fair Play Committee of the United Nations Educational, Scientific and Cultural Organization (UNESCO) in 1975.

Zátopek died aged 78 in Prague in November 2000, but in 2012 it was inaugurated into the International Association of Athletics Federations, now World Athletics, Hall of Fame.

RunCzech President Carlo Capalbo said the campaign has now been amended, with the letter Z removed due to its association with the war in Ukraine.

"A few weeks ago, we launched a campaign on social media and in the press to support the phenomenon of running by commemorating 100 years since the birth of Emil Zátopek and 70 years since winning his three Olympic gold medals," Capalbo said.

"The advertising campaign was created by leading creatives and counted on the gradual discovery of the entire message from the unfortunate letter Z to visuals with a running legend and messages like 'This season is all about Z' or 'RunCzech remember'.

"Even though it is just a letter of the alphabet, which is supposed to remind a Czech phenomenal athlete, we do not want it to be associated with aggression and evoke unpleasant emotions.

"I have always been against the politicisation of sports and running separately.

"The current circumstances are changing things, and we are considering a form of symbolic support and expression of the peaceful message, unity and spirit of fair play.

"Especially in these difficult times."

The letter Z has been seen on Russian military vehicles and artillery during the ongoing war in Ukraine.

Russia's Ministry of Defence has reportedly claimed the Z symbol means "For Victory".

The symbol was controversially displayed by Russian gymnast Ivan Kuliak earlier this month at a Gymnastics World Cup event in Doha.

The gymnast now faces disciplinary action from the International Gymnastics Federation (FIG).

RunCzech, which organises the Prague Marathon and Prague Half Marathon, has said it is following decisions taken by Czech and international sports organisations.

The organisation said Ukrainian athletes who have registered for its events and are unable to attend due to the war will be refunded their entry fees.