Members of the armed forces take part in a ceremony at the Cross of Reconciliation in Ieper, Belgium to commemorate the first gas attack in the First World War, on April 22, 2015
Brussels (AFP) - Belgium marked the 100th anniversary Wednesday of the first large-scale use of chemical weapons on the battlefield with calls for greater efforts to ban the use of poisonous gas.
On April 22 1915, German forces seeking to break the stalemate of World War 1 trench warfare pumped chlorine gas towards allied positions just northeast of the small Belgian town of Ypres.
The gas killed some 1,500 soldiers and injured many more but the attack failed to change the course of the war, with German troops failing to fully capitalise on the deadly mayhem they created.
Some 250 school children took part in a ceremony Wednesday in Ypres' central square, which was totally destroyed in the war but has been carefully rebuilt since.
Belgian King Philippe attended ceremonies at the site of the attack and then paid hommage at a monument to Canadians troops who died trying to plug the gap in the lines at Ypres caused by the gas attack.
"This first attack ... ushered in months of fighting in which another five gas attacks were made in what became known as the Second Battle of Ypres," Flanders regional head Geert Bourgeois said.
"Next came the chemical arms race in which all sides developed gas weapons, one more deadly than the other," Bourgeois said.
"One hundred years after these atrocities, these weapons are still in use. Only recently, chemical weapons have been used in the Syrian civil war," he added.
Chlorine and other weapons such as Mustard Gas -- dubbed 'Yperite' after its first use by the Germans near the town in 1917 -- turned out to be unpredictable and dangerous also for the attacker, but had a huge psychological impact on the battlefield and at home.
The attacks inflicted minimal casualties, however, compared with the millions slain by artillery and machine gun fire.
The International Committee of the Red Cross seized on the anniversary to call for redoubled efforts to prevent the use of chemical weapons.
Evoking several reported gas attacks in Syria ICRC vice president Christine Beerli said in Ypres that there "was an urgent need for more progress towards ridding the world of all types of weapons of mass destruction."
The use of chlorine gas as a weapon was banned after WWI but Beerli noted that had not prevented the horrors seen in Syria, where President Bashar al-Assad's regime has been accused by the opposition of carrying out chlorine gas attacks.
“It is therefore our duty to work not only for the law to exist. But also for it to be understood, to be accepted and to be respected," she said.