Nobel laureates urged Xi Jinping to free detained Chinese dissident and Nobel Peace Prize winner Liu Xiaobo and his wife as the newly appointed Chinese Communist Party chief assumes presidency in March.

“We respectfully urge you to release Dr. Liu Xiaobo, the world’s only imprisoned Nobel Peace Prize Laureate, and his wife, Liu Xia,” the laureates wrote in a letter released on Tuesday, which was signed by 134 Nobel laureates, including the Dalai Lama and South African peace campaigner Desmond Tutu.

The laureates also cited that President Hu Jintao recognized that much is needed to be done on human rights in China.

“While we welcome such honest assessments, we hope that China’s new political leadership will move past merely recognizing the problem and seize this important opportunity to take concrete steps towards embracing the fundamental rights of all Chinese citizens,” they wrote.

“No government can restrict freedom of thought and association without having a negative effect on such important human innovation.”

Liu won the Nobel Peace Prize in 2010 for his “long and non-violent struggle for human rights in China” but was barred from attending the awarding ceremony in Oslo. Liu had been sentenced to 11 years imprisonment for “attempted subversion of power” while his wife, Liu Xia, is under house arrest, Reuters reports.