A Saudi court on Thursday issued harsh jail terms against two human rights defenders despite reforms touted by the kingdom's crown prince, Amnesty International said.

The court in Riyadh sentenced Mohammad al-Otaibi and Abdullah al-Attawi to 14 and seven years imprisonment, respectively, the rights group said.

“The harsh sentencing... confirms our fears that the new leadership of [Crown Prince] Mohamed bin Salman is determined to silence civil society and human rights defenders in the kingdom,” said Samir Hadid, director of campaigns for the Middle East at Amnesty.

“The crackdown on members of the human rights community has continued unabated, with almost all the country's most prominent human rights defenders now behind bars,” she said.

Otaibi and Attawi were charged with participating in setting up an organisation and announcing it before securing an authorisation. They were also accused of dividing national unity, spreading chaos and inciting public opinion by publishing statements harmful to the kingdom's image and its judicial and security agencies, Amnesty said.

Otaibi, 49, fled to neighbouring Qatar in March last year and was extradited to the kingdom two months later. He co-founded the Union for Human Rights in Riyadh in 2013 and authorities ordered it shut after about one month, but he continued his work.

“If Crown Prince Mohammad bin Salman is truly intent on bringing reforms to Saudi Arabia, he must ensure the immediate and unconditional release of all prisoners of conscience, including human rights defenders, detained solely for peacefully exercising their human rights,” Hadid said.