Cyclone Shaheen has claimed the lives of 13 people as it swept across Oman and Iran amid fears the death toll could rise further.
The authorities in Oman said the toll included a child who drowned and two people from Asia who were killed in a landslide.
The body of a man who disappeared when floodwaters swept him away from his vehicle had also been recovered.
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Four people were killed on Sunday with the authorities announcing a further seven had died as search and rescue operations continued.
In Iran, state television said rescuers found the bodies of two of five fishermen who went missing off Pasabandar, a village near the border with Pakistan.
It took the storm’s overall death toll to 13 – but the Iranian deputy parliament speaker Ali Nikzad said he feared as many as six fishermen could have been killed because of the conditions.
Winds reached up to 93mph (150kmph) as it made landfall in the region, throwing waves up to 10m (33ft) high and leaving behind damage to buildings and widespread flooding.
Meteorologists later downgraded the cyclone to a tropical storm with experts predicting the winds will continue to weaken in the coming hours.
Thousands of people had been evacuated from coastal areas in Oman ahead of the storm’s arrival, while the conditions brought flooding to the nation’s capital, Muscat.
Omani state television broadcast images of flooded roads and valleys as the storm moved deeper inland, with its outer edges reaching the neighbouring United Arab Emirates.
Officials in Oman urged people to be careful crossing valleys and to avoid low lying areas, with some individuals needing to be rescued by helicopter.
Further heavy rain was expected in some areas, raising the risk of flash floods.
A cyclone is the same as a hurricane or a typhoon. Hurricanes originate east of the international date line – typhoons develop west of the line.
They are known as cyclones in the Indian Ocean and Australia.