Iran's President Hassan Rouhani warned of a Covid-19 “fourth wave” as cases rise in certain areas of the Middle Eastern country hardest hit by the pandemic.

“This is a warning for all of us,” Rouhani said in televised remarks.

He said some cities in the southwestern province of Khuzestan were now “red” — the highest on Iran's colour-coded risk level — after weeks of low alert levels across the country.

“This means the beginning of moving towards the fourth wave. We all have to be vigilant to prevent this,” Rouhani added.