"Let everyone play their part in the best way to break the chain of transmission in the short term and save the country," Ayatollah Ali Khamenei said in a video conference with lawmakers, according to his office. 

Iran has been struggling to contain the outbreak since announcing its first cases in February, and has reported more than 12,800 deaths since then.

Khamenei's speech was his first to MPs since the new parliament took office at the end of May, dominated by conservatives and ultra-conservatives elected in February polls. 

According to his official site, Khamenei praised healthcare workers for "their sacrifices".

But he also strongly criticized "some people who do not even do something as simple as wearing a mask", saying he felt "ashamed" of such behavior. 

Khamenei's comments came as infections have again been on the rise in Iran since early May. 

According to figures announced Sunday, 194 deaths from the COVID-19 disease and 2,186 new cases were recorded in the past 24 hours. 

The health ministry announced a record 221 deaths in a single day on Thursday. 

In total, 257,303 cases have been reported in the country, including 12,829 deaths, health ministry spokeswoman Sima Sadat Lari said Sunday in a televised press conference. 

The rising toll has prompted authorities to make masks mandatory in enclosed public spaces and to allow the hardest-hit provinces to reimpose other measures against the virus.

Iran had closed schools, cancelled public events and banned movement between its 31 provinces in March, but the government progressively lifted restrictions from April to reopen its sanctions-hit economy.

On Saturday, President Hassan Rouhani said the country could not afford to shut down the economy, even as the outbreak worsened.

Iran must continue "economic, social and cultural activities while observing health protocols", Rouhani said during a televised virus taskforce meeting.

But he reminded Iranians that restrictions, such as a ban on public and private gatherings, remained in place.

"Gatherings, whether for funerals, weddings, parties, seminars or festivals are all harmful" to public health, Rouhani said.

Authorities have previously reported the spread of the virus in areas where such bans had been ignored.

On Sunday, Khamenei also told lawmakers that "parliament has the right to question... but is not permitted to insult or slander government officials".

His comments came a week after a session in which MPs heckled Foreign Minister Mohammad Javad Zarif, largely over his key role in negotiating a 2015 nuclear deal with world powers.

The deal had given the Islamic republic relief from international sanctions in return for limits on its nuclear program, but Iranian conservatives staunchly opposed the multilateral agreement, arguing the US could never be trusted.

The US unilaterally abandoned the accord in 2018 as a prelude to reimposing biting sanctions.