"Sixteen people, including nine Omanis, have been found dead," police spokesman Abdullah al-Harthy told AFP.

The official ONA news agency had Tuesday given a toll of 14.

The Asha Enterprises construction company said three Indian employees were still missing after their truck was swept up by a flash flood in the capital Muscat. One passenger, carpenter Ram Kishore Bairwa, was found dead, while a fifth, Sukhdip Singh, escaped.

"We haven't lost hope. Miracles do happen," said M.A. Surendran of Asha Enterprises.

The storm late Monday caused extensive damage to property, uprooting vegetation and causing power cuts. Nizwa, 200 kilometres (120 miles) southwest of Muscat, was hit by 66 millimetres (2.6 inches) of rain, while the capital received 23 millimetres (0.9 inches).

More rain is possible this week in the sultanate, meteorologists said.

SPACE.WIRE