Saudi Arabia announced it had carried out four executions in different cities on Wednesday morning, bringing the total number of judicial killings to 130 so far in 2015, a sharp rise on recent years.

Three executions were of Saudi nationals convicted of murder. They were executed in Asir Province, the city of Taif and al-Baha Province respectively . A Syrian man was executed in the northern province of al-Jawf for drug smuggling.

Most executions in Saudi Arabia are done by public beheading.

Analysts say it is not clear why the number of executions in Saudi Arabia has increased so much from last year, when 88 people were put to death, or 2013, when it executed at least 64.

Some diplomats in Riyadh have said that judicial reforms, including the appointment of more judges, have allowed a backlog of appeals cases to be heard, leading to a short-term rise in executions.  - Reuters