Turkish activist Osman Kavala said Friday the top appeals court's decision to uphold his life sentence violated the rule of law and human life.

Kavala, a Paris-born activist and philanthropist, was sentenced in April to life in prison without the chance of parole on the allegation of attempting to destabilize the government by supporting street protests in 2013.

Seven others were sentenced to 18 years in prison for supporting the overthrow of then-Prime Minister Erdogan's government during the so-called Gezi Park demonstrations in Istanbul.

The decision drew outrage from countries throughout the world, including the United States, Germany, and France, as well as international rights organizations.

The United States and major European powers have been pushing Turkey for the release of Kavala - a case that has strained ties between Turkey and the West. The rising tensions have recently led to Turkey's expulsion of 10 ambassadors. 

Since his sudden arrest in October 2017, Kavala's years-long trial has been gnawing at Turkey's strategic but volatile ties with its main Western partners.

On Thursday, Turkey's top appeals court affirmed Kavala's life sentence despite reversing jail convictions for three other civil society leaders in the same case, who were later freed on probation.

On Friday, Enis Berberoglu, an opposition legislator who has served time in prison, paid a visit to Kavala and noted that he saw him "in good morale."

Berberoglu told AFP that "(Kavala) told me he saw the court decision on television last night while writing a letter," adding that Kavala's reaction was that he knew the decision was a result of an "understanding that does not value law or human life".

Amnesty International called the verdict an "appalling and politically motivated" attempt to "silence independent voices."

Europe Ruth Tanner, Amnesty's director for Europe stated that the decision was also a "blow for human rights" that "defies all logic given that the prosecuting authorities have repeatedly failed to provide any evidence to substantiate the baseless charges laid against them."