Khamenei expressed his deep regret over a spike in coronavirus infections and the rise of daily deaths, according to Press TV.
Referring to the initial "success" of the Iranian health authorities in fighting the novel coronavirus, Khamenei said Iran is "certainly capable of overcoming the disease."
He urged government institutions, aid groups and the entire nation to "play their role in the best way so that we can break the infection chain in the short term and lead the country to the shore of safety."
The Iranian leader touched on Iran's economic problems arising from the US sanctions as the country is battling the COVID-19 pandemic, reports Xinhua .
Iran has reimposed some restrictions on the cities in parts of the country amid the resurgence of COVID-19 infections and fatalities.
On Sunday, Iran's confirmed coronavirus cases rose to 257,303 after an overnight registration of 2,186 new infections, state-run IRNA news agency reported.
Sima Sadat Lari, spokeswoman for Iran's Ministry of Health and Medical Education, said during her daily briefing that out of the new cases in the past 24 hours, 1,499 have been hospitalised.
The pandemic has so far claimed the lives of 12,829 Iranians, up by 194 in the past 24 hours.