Choirs from across the world joined their voices to sing for peace in Ukraine Sunday, with nearly 300 singers gathering in Madrid where the initiative began a year ago.

Under cloudless blue skies, singers from 46 choirs in and around the Spanish capital gathered outside the Reina Sofia art museum and began singing at midday (1000 GMT) in an event involving thousands of others across Europe and Latin America.

This year, choirs joined from 81 locations in nine countries, with 1,000 singers from Ukraine joining their voices with others from Argentina, Brazil, Colombia, Denmark, Germany, Portugal and Venezuela.

Standing in the museum square, they sang "Dona Nobis Pacem," the Hebrew slaves' chorus from Verdi's Nabucco and finally "Sing an Anthem for Our Peace," which was written specially by U.S. composer Jim Papoulis.

The simultaneous event, which was broadcast live on YouTube, was organized by Choirs for Peace, an initiative started by Madrid choir a month after Russia's invasion of Ukraine whose first event drew over 25,000 singers.

"We are here to support Ukraine and say we need peace now, that we have to stop this war," said Elvira Polyenova, a 48-year-old Ukrainian soprano who used to perform at the Odesa opera house, and who sang the opening solo in "There is Peace."

"Music unites people, so the choir is a perfect instrument for spreading messages of peace and unity," said Mariano Garcia, choir director at Santiago Apostol church which started Choirs for Peace last year.

"Although its power of influence is limited, we believe all choral music has the capacity to make us all a little more aware ... and might even reach those with the capacity to decide," he told AFP.

After seeing last year's event, Elena Redondo, 54, decided to join a choir so she could be part of this year's initiative.

"We all forget there's not only this war in Ukraine but others all over the world, and we seem to get used to it. So, events like this are an important wake-up call," she said. "Music changes many things, not only on a global level, but also on an individual level, it really changes the way you see things. I think it's important to join together with other voices."