Iran on Thursday announced 87 new deaths from the novel coronavirus as authorities moved to tighten measures to stop its spread in some of the country's worst-hit provinces.

Health ministry spokeswoman Sima Sadat Lari said in a televised interview that the fatalities in the past 24 hours had taken the overall toll in Iran's outbreak to 9,272. She added that another 2,596 people had tested positive for COVID-19, bringing to 197,647 the total number of confirmed cases since the outbreak emerged almost four months ago.

Five of Iran's 31 provinces -- Bushehr, East Azerbaijan, Hormozgan, Kermanshah and Khuzestan -- were currently "red", the highest level on the country's colour-coded risk scale. East Azerbaijan was set to reimpose restrictive measures, according to state news agency IRNA. "Limitations will be reimposed due to the rising number of coronavirus infections and deaths in the province," deputy governor Aliar Rastgou said.

Rastgou said the situation was "dangerous" as residents were failing to observe social distancing and other measures under health protocols aimed at halting COVID-19. Hormozgan had also shut down all non-essential businesses, parks and government organisations, and reimposed an inter-city travel ban at least until Saturday, state television said.

Khuzestan was the first province to see a reimposed lockdown over a worsening situation after the government gradually lifted protocols from April in order to reopen its sanctions-hit economy. Other provinces such as Golestan as well as Kohgiluyeh and Boyerahmad have also reimposed measures such as checkpoints at city entrances.

Iran reported its first virus 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.

The Islamic republic says the recent upsurge is due to increased testing rather than a worsening outbreak. There has been scepticism at home and abroad about Iran's official figures, with concerns the real toll could be much higher.