At least 19 people have been beheaded in Saudi Arabia this month for offences including drug smuggling and sorcery, according to Human Rights Watch (HRW).

The dead include four Saudi men executed in Najran province on Monday for smuggling hashish, and two foreigners - a Syrian and a Pakistani, accused of the same crime.

Authorities beheaded Saudi national, Mohammed bin Bakr al-Alawi, on August 5 for allegedly practicing sorcery, the Saudi Gazette reported.

The family of another man, Hajras bin Saleh al-Qurey, who suffers from a mental disability, fear his execution for drug smuggling is imminent.

Doctors who examined him confirmed he had symptoms of mental illness, but concluded that he should be held criminally liable.

Qurey said investigators had pressured him in to confess by placing him in solitary confinement, according to the statement by HRW, which relied on local news reports, court documents and interviews with relatives.

'Disturbing surge'

On Wednesday, Saudi authorities executed a Pakistani national for the murder of an Afghan man, the AFP news agency reported.

At least 34 people have been put to death in the country in 2014, including the 19 people killed in August.

Amnesty International denounced what it called a "disturbing surge" and called on the Saudi government to immediately halt all executions.

"Any execution is appalling, but executions for crimes such as drug smuggling or sorcery that result in no loss of life are particularly egregious," said HRW's Sarah Leah Watson.

"The current surge in executions in Saudi Arabia is yet another dark stain on the kingdom’s human rights record."

The kingdom reserves the death penalty for crimes including murder, robbery, drug smuggling, blasphemy and drug smuggling.