People in Bahrain have been invited to attend rallies on Thursday and Friday to voice support for prominent Shia cleric Ayatollah Sheikh Nimr Baqir al-Nimr.
The Islamic Wafa opposition group has urged Bahrainis to take part in the rallies.
Ayatollah Nimr has been in detention since July 2012 has been sentenced to death by a Saudi court.
Saudi Arabia’s Court of Appeals and Supreme Court have approved the death sentence handed to the senior Shia cleric.
According to some media outlets, the death sentence has been referred to the interior ministry and then the king’s office for the final go-ahead.
Nimr’s lawyer, Sadeq al-Jubran, has also said that Nimr could be executed as soon as the Saudi monarch approves his sentence.
The Islamic Wafa opposition group in a statement slammed the decision, warning the Al-Saud regime of the consequences of carrying out the verdict.
It also called on the international community and human rights bodies to take steps to prevent the execution of Ayatollah Nimr.