Mo, speaking at a news conference in Shandong province, suggested he is not a fan of Liu's essays pushing for democracy in China and made no direct demands on the government, The New York Times reported. But he did give a short statement of support.
"I hope he can achieve his freedom as soon as possible," Mo said.
Mo, 57, is the first Chinese writer to win the literature prize. Two dissidents suggested they welcomed even a tempered statement of support for Liu, who won the peace prize in 2010.
"Maybe all the glory has made him more courageous and more outspoken," Murong Xuecunhe, a writer who has confronted the government, said of Mo.