Riyadh: Four more people have died of the Middle East respiratory syndrome coronavirus (Mers-CoV,), raising the toll to 400, a media report said on Tuesday.

The health ministry on Monday said all the victims were men, local media reported.

Three of the victims, aged 91, 89 and 60, were from Riyadh and the fourth was a 45-year-old foreign worker in the central city of Buraidah, the ministry said.

All four had pre-existing diseases prior to catching the coronavirus.

Most other Mers deaths have pre-existing diseases, ministry records have shown.

Four new infections were also reported, bringing the total number of Mers-CoV cases in Saudi Arabia to 931 since June 2012.

All the new cases were reported in Riyadh. Three are Saudis — a 61-year-old woman, a 63-year-old man and another man aged 53 — and the fourth is a male expatriate worker aged 57.

Two of the cases are listed to be in “critical” condition.

The World Health Organisation (WHO) has cited the preliminary results of studies indicating that people working with camels are at high risk of infection from Mers-CoV, and young camels are particularly susceptible.