Iran on Wednesday offered condolences to the families of four Saudis who died from an apparent accidental chemical poisoning during a pilgrimage in Iran, after Riyadh summoned Tehran's ambassador over the incident.
Thirty-six Saudis on a pilgrimage to the Shia holy city of Mashhad were hospitalised Sunday morning, suffering from nausea and dizziness, Abdullah Bahrami, the director of the Imam Reza hospital, was quoted as saying by official news agency IRNA.
Four, three children and a teenager, died in the hospital after inhaling toxic gas at the hotel in Mashhad, Iranian media reported.
Saudi officials on Tuesday called for Iranian authorities to "quickly carry out investigation procedures" into the incident.
"Iranians are well-known for their hospitality and we hope this issue is resolved," said Marzieh Afkham, Iran's foreign ministry spokeswoman, expressing sympathy and condolences.
A senior Iranian official Wednesday said the incident had no "political or international" links.
"All the investigations reject a deliberate intention behind the incident and the hotel manager has accepted responsiblity for this negligence," IRNA quoted interior ministry official Hossein Zolfaghari as saying.
He said the poisonings had been the result of illegal pesticide use leaking through ventilation into the area of the hotel where the Saudis were staying.
The hotel manager and four others were taken in for questioning.
Nine pilgrims were still in hospital on Tuesday.
Home to the shrine of Imam Reza, Mashhad draws millions of Shia Muslim pilgrims each year from Iran and abroad.
The incident came with tensions high between Sunni-dominated Saudi Arabia and its Shia regional rival Iran.
Saudi Arabia leads an Arab-dominated coalition which for more than two months has been bombing Iran-backed Shia rebels in Yemen.
The kingdom's Shia minority has also been grieving over the murder of 25 people blown up in two separate suicide bombings at mosques in eastern Saudi Arabia last month.
Both attacks were claimed by the Islamic State jihadist group, a Sunni extremist organisation that considers Shias to be heretics.