Chinese writer and democracy activist Li Tie has been sentenced to 10 years in prison after penning a series of essays urging citizens to defend their rights.

A relative of the activist said Thursday Li was found guilty of “subversion of state power” by a court in central China earlier this week.

The relative says Li maintained his innocence throughout the trial, and that the court refused to allow him to choose his own attorney.

Rights groups say the 52-year-old activist was jailed for posting online articles that criticized the government and promoted democracy.

He is the third Chinese dissident in less than a month to receive a lengthy prison sentence for inciting subversion.

In December, Chinese courts gave a nine year prison sentence to veteran democracy activist Chen Wei and jailed fellow activist Chen Xi for 10 years after they posted online articles that the government deemed subversive.

The sentences are part of a wider crackdown on dissent that is believed to be aimed at preventing anti-government protests like those that have swept across much of the Arab world.

On Monday, U.S. Ambassador to Beijing Gary Locke said China's human rights record is deteriorating in the face of pro-democracy protests in the Middle East. He said China's human rights climate is “in a down period and it's getting worse.”

But China's foreign ministry rejected the claim. It said that Beijing respects human rights and is only arresting those in violation of Chinese law.

Activists say they expect increased monitoring and arrests ahead of a pivotal transition in Chinese communist party leadership that is scheduled for later in the year.