Four Saudi citizens have died from poisoning in the northeastern Iranian city of Mashhad, hospital and�judiciary�officials confirm.��

The incident happened on�Sunday when a group of 33 Saudi pilgrims were hospitalized with poisoning symptoms, said Abdollah Bahrami head of Imam Reza Hospital in Mashhad.

He added that four Saudi children lost their lives despite extensive treatment by Iranian medical staff.

The Saudi pilgrims were staying at a hotel in the holy city of Mashhad in Khorassan Razavi province which houses the shrine of Imam Reza,�the eighth Imam of Shia Muslims.

Meanwhile, Mashhad Prosecutor Gholam Ali Sadeqi also said a probe has been launched into the case.

"A special inspector has been designated to immediately look into all aspects and probable causes of the incident," said the prosecutor.

The preliminary investigation rules out foul play in the deaths of the Saudi nationals, he noted.

"In the initial investigation, no evidence showing�the incident was a deliberate act was found" the prosecutor noted.

Mashhad is the spiritual capital of Iran and it owes its significance to the Imam Reza shrine, which draws�almost millions of pilgrims from around the world every year.

By Press TV