Oman on Wednesday banned the import of bottled water from Iran after the deaths of two people who drank from a contaminated batch.
An expat woman died on Monday, the Royal Oman Police said, and an Omani man died in hospital on Wednesday after being in a critical condition for two days.
Members of the Omani family were also poisoned but have recovered, the force added.
The source of the poisoning in the Wilayat of Suwaiq area was a contaminated batch of bottled water from the Iranian brand Uranus Star.
Police co-ordinated with authorities to collect samples of the water, and laboratory tests confirmed that they were contaminated.
Omani authorities have begun withdrawing Uranus Star products from local markets while investigations continue.
Royal Oman Police warned citizens and residents against drinking Uranus Star water.
