Iran on Wednesday reported more than 100 deaths from the novel coronavirus for a fourth straight day, saying that gatherings in high-risk provinces have led to a spike in infections.

"Holding gatherings such as weddings and funerals is one of the main causes of increased coronavirus infections in red provinces," the highest level on Iran's colour-coded risk scale, said deputy health minister Iraj Harirchi. "In one province, 120 people were infected at a single wedding," the ISNA news agency quoted him as saying.

Health ministry spokeswoman Sima Sadat Lari said 120 new deaths in the past 24 hours took Iran's overall toll to 9,158. This is Iran's highest single-day death toll since April 11. Lari added that another 2,612 tested positive for COVID-19, bringing total confirmed cases to 195,051. Iran reported its first coronavirus cases on February 19, and it has since struggled to contain the outbreak.

Official figures have shown a rising trajectory in new confirmed cases since early May, when Iran hit a near two-month low in daily recorded infections. There has been scepticism at home and abroad about Iran's official figures, with concerns the real toll could be much higher.