More than 1,000 writers from around the world, including Salman Rushdie, Margaret Atwood and Nobel laureate Orhan Pamuk, have expressed solidarity for the people of Ukraine enduring "their darkest hours".
In a letter organised by the campaign group PEN International, and sent also in Ukrainian and Russian, the authors demanded Russian President Vladimir Putin end his invasion of Ukraine.
"We stand united in condemnation of a senseless war, waged by President Putin's refusal to accept the rights of Ukraine's people to debate their future allegiance and history without Moscow's interference," they wrote.
"We stand united in support of writers, journalists, artists, and all the people of Ukraine, who are living through their darkest hours. We stand by you and feel your pain."
Other signatories included Maria Ressa, the Philippine journalist who won last year's Nobel Peace Prize jointly with Dmitry Muratov, the editor-in-chief of Russian opposition newspaper Novaya Gazeta.
In an online video, Muratov has expressed his "shame" at Putin's invasion.