A Turkish appellate court on Wednesday upheld the conviction of a leading critic of President Recep Tayyip Erdogan whose jailing has added to tensions in Ankara's uneasy ties with the West. Paris-born activist and philanthropist Osman Kavala was sentenced to life in jail without the possibility of parole in April on the charge of trying to topple the government by financing street protests in 2013, AFP said. Seven others were jailed for 18 years each for aiding the attempt to overthrow the government of then-prime minister Erdogan during the so-called Gezi Park rallies in Istanbul. The Anadolu state news agency said the appellate court ruled that the April verdict "complied with the law". The defense can still appeal the case in Türkiye’s Supreme Court. Kavala's years-long trial has been gnawing on NATO member Türkiye’s strategic but tempestuous ties with its main Western allies since his unexpected arrest in October 2017. Kavala was then best known as a soft-spoken businessman who was spending part of his wealth to promote culture and projects aimed at reconciling Türkiye and its arch-nemesis Armenia. But Erdogan portrayed him as a leftist agent of the Hungarian-born US billionaire George Soros who was using foreign money to try and overthrow the state. Kavala was first charged with funding the wave of 2013 protests that some analysts view as the genesis of Erdogan's more authoritarian posture in the latter half of his two-decade rule. A court acquitted and released him in February 2020 -- only for the police to arrest him before he had a chance to return home to his wife. Another court then accused him of being involved in a failed 2016 coup attempt against Erdogan in which more than 250 died in Istanbul and Ankara. Kavala ultimately ended up facing both sets of charges. The court ultimately convicted him of the same set of charges of which he had been cleared in 2020. Germany demanded his immediate release while the United States said it was "deeply troubled" by the ruling. "His unjust conviction is inconsistent with respect for human rights and the rule of law. We again call on Türkiye to release Osman Kavala," said Vedant Patel, a spokesman with the US State Department. "The people of Türkiye deserve to exercise their human rights and fundamental freedoms without fear of retribution." Türkiye has already ignored a European Court of Human Rights ruling demanding Kavala's release.