Cole described Yee as a "young political dissident," saying "his prosecution, detention and general maltreatment at the hands of Singapore authorities constitute persecution on account of Yee's political opinions."

Trouble with authorities in Singapore

In July 2015, Yee was detained for 53 days after he posted a YouTube tirade praising the death of Singapore's first Prime Minister, Lee Kuan Yew. Yee described the politician as "totalitarian" and compared him unfavorably to Jesus and Mao Zedong.

In another incident in September last year, Yee was sentenced to six weeks in prison for controversial religious posts that he wrote and shared on social media.

In that case, a court found him guilty of eight charges: six related to "wounding religious feelings" and two for his failure to turn up at a police station when summoned.

"He has, on several occasions, deliberately elected to do harm by using offensive and insulting words and profane gestures to hurt the feelings of Christians and Muslims," principal district judge Ong Hian Sun wrote in court documents obtained by CNN at the time.

The prosperous Southeast Asian city-state of Singapore -- with an estimated population of 5.7 million -- is ethnically and religiously diverse.

Critics have said his arrest and subsequent detention highlighted the restrictions on free speech in Singapore, where criticism of leaders and the government is frowned upon.