The visual protest at Kallio of the Evangelical Lutheran Church of Finland in Helsinki was displayed on Monday ahead of Donald Trump and Vladimir Putin's meeting in the capital.
The charity and the parish said in a statement that the purpose of the high bell tower banners was "to remind all those whose eyes are on Helsinki on this day that empathy and action are the keys to protecting the planet from climate change and environmental destruction".
It went on to state: "Greenpeace is committed to a peaceful world where the environment is protected. Real leaders put Planet Earth first and tackle urgent global threats such as climate change, destruction of forests and the unprecedented pressure on our oceans."
The world's two most powerful men will have behind-closed-doors talks and have not set an agenda for their one-to-one discussions.
Landed in #Finland for #helsinki2018 where @POTUS & Prez Putin are set to discuss US/Russian relations. POTUS meeting is in the interest of US national security. It's critical that the leaders of the US & Russia engage on important matters between our two countries. @StateDept pic.twitter.com/ZdNN6fHPTi
— Secretary Pompeo (@SecPompeo) July 15, 2018
However, Mr Trump has admitted he doesn't have high hopes for the summit and tweeted: "Our relationship with Russia has never been worse thanks to many years of US foolishness and stupidity and now, the rigged witch hunt!"
The meeting comes amid speculation about whether Mr Trump will rebuke his Russian counterpart for the election meddling that prompted a special counsel probe that he has repeatedly labelled a witch hunt.
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