The Prime Minister's arrival in Tehran on Sunday came two days after Iran released a South Korean-flagged tanker seized three months ago in the Gulf for violating environmental regulations and marine pollution.
The produced vaccines will be supplied domestically.
South Korea also plans to step up quarantine measures on sailors coming from Russia and other countries that are in Seoul's list of nations subject to tougher quarantine, the Prime Minister also said.
It is the first time that the number of daily new infections fell below 20 since May 9 when the single-day cases hit 18.
Of the newly added cases, 17 were connected to bars and clubs in Seoul's popular night-life district of Itaewon between April 24 and May 6
In total, the outbreak has so far led to a total of 131 infections, some of them at the secondary and tertiary levels.
At least 1,138 infections have been linked to international arrivals, but such cases have declined after the country strengthened border controls in April, enforcing two-week quarantines on all passengers coming from abroad.
With around 7,200 people estimated to have visited the five establishments, health authorities have warned of a further spike in infections and have asked those who went to any of the venues to get tested.
The country once had the largest outbreak outside China, where the disease first emerged in December last year, but appears to have brought it under control with an extensive “trace, test and treat” programme.
Firefighters brought in excavators to search every corner of the warehouse as they struggle to confirm if any more victims remain in the wreckage.
