In perfect symphony, orchestras and choir singers performed Beethoven's "Ode to Joy" in flashmobs at seven airports across Ukraine on Sunday in tribute to those who died in the country's revolution.

At Kiev's Zhuliany airport the presidential and national orchestras united to play the famous tune which is also the European anthem, a fitting show of support for Ukraine's efforts to move closer to the EU that plunged the nation into crisis.

As uniformed band members struck up their instruments, choir singers disguised as normal members of the public moved into position between the musicians and began to sing along.

Children were hoisted onto their fathers' shoulders as people gathered around, many filming the performance with their smartphones.

Organisers said in a statement that the performances took place at 1:00pm local time at seven airports including Kiev's Boryspil airport and those in the cities of Lviv (west), Odessa (southwest), Donetsk, Karkhiv and Dnipropetrovsk in the country's heavily Russified east.

The action marked 40 days since the deadliest day of three months of protests as Ukrainians revolted against President Viktor Yanukovych's pro-Moscow government.

Some 100 people died in total during the uprising and are referred to in Ukraine as the "Heavenly Hundred".

"The aim is to commemorate the memory of the fallen. It is also to show the unity and sovereignty of Ukraine," said the statement.

In the Orthodox tradition the 40th day after a death marks the end of a period of mourning and is marked with a special memorial service.

Thousands of mourners on Sunday also visited Kiev's Independence Square, the heart of the protest movement, many shedding tears as they laid fresh flowers around makeshift shrines and barricades perfectly preserved since the street battles ended.

"I want my children to know what we went through and to remember these people who gave their lives for their future," said Volodymyr, a computer engineer visiting the site with his two children.

The "Ode to Joy" flashmobs were also a celebration of the signing of an Association Agreement with the EU, organisers said.

Kiev's new leaders on March 21 signed the deal which Yanukovych had rejected four months earlier in favour of closer ties with Moscow, sparking the uprising which would eventually see him removed by parliament.

Ukrainian artists have been actively involved in the pro-European revolution.

Pop star Ruslana once spent up to 10 hours on stage at Kiev's Independence Square, the heart of the protest movement, as she sang to lift the spirits of protesters facing off against security forces in the freezing cold.

Earlier on in the uprising, a piano painted blue and yellow -- the colours of the Ukrainian flag -- was placed in front of an imposing line of Berkut riot police for anyone to play, an effort to lift the grim mood and meet violence with art.

And this week musician and activist Nikita Rubchenko recorded a rock version of Ukraine's national anthem -- complete with guitar riffs and drum beats -- that scored over 350,000 hits on YouTube.

Organisers of Sunday's orchestral flashmob said they aimed to unite the fractured country though music.

The turmoil has sharpened divisions between the country's pro-European west and heavily Russified east.