Court documents obtained by the two human rights groups showed that a total of 38 defendants, including the 14 sentenced to death, were convicted of charges linked to demonstrations in the eastern province of Qatif in 2011 and 2012.
Most had been held in pretrial detention for more than two years, many of them in solitary confinement, the groups said, according to the official website of Amnesty International.
"The rise in death sentences against Saudi Arabian Shiites is alarming and suggests that the authorities are using the death penalty to settle scores and crush dissent under the guise of combating ‘terrorism’ and maintaining national security,” said Sarah Leah Whitson of Human Rights Watch.
Amnesty International’s Lynn Maalouf said the death sentences, handed down in 2016 and upheld last month, were based on coerced confessions that were later retracted.
Maalouf said the verdicts were based on "sham court proceedings … that brazenly flout international fair trial standards” and should be overturned.
Saudi Arabia carried out 153 executions across the kingdom last year. In the most stunning case of executions in 2016, Saudi Arabia executed on January 2 Sheikh Nimr al-Nimr along 46 other people in defiance of international calls for the release of the prominent Shiite cleric and other jailed political dissidents in the kingdom.
Saudi Arabia carried out 158 executions, including 71 foreign nationals, in 2015. This number of executions in terms of annual basis in Saudi Arabia has been unseen since 1995.
Saudi officials execute convicts by sword and then dangle their corpses from a helicopter to make sure the public could see the result of the execution.
According to the Amnesty, Saudi Arabia has one of the highest execution rates in the world. Human Rights Watch has on multiple occasions called on the Saudi regime to abolish its "ghastly” beheadings.