A first batch of Russia's Sputnik V vaccine arrived Thursday in Iran, the regional country hardest hit by the pandemic, which has charged US sanctions have hindered its fight against Covid-19.

"The first shipment of vaccines from Moscow... has landed at Imam Khomeini airport in Tehran," state news agency IRNA reported without specifying the quantity of doses.

The second and third deliveries of the vaccine were due to be sent to Tehran on February 18 and 28, IRNA quoted Kazem Jalali, Iran's ambassador to Moscow, as saying.

Iran's supreme leader Ayatollah Ali Khamenei had last month banned vaccines made by the United States and Britain, calling them "completely untrustworthy".

The Islamic republic is fighting the Middle East's deadliest outbreak of the coronavirus, with over 58,000 lives lost out of more than 1.4 million cases.

Announcing the new figures on Thursday, health ministry spokeswoman Sima Sadat Lari warned that the situation in the country was "sensitive and fragile".

Iran says arch enemy the United States has blocked its access to vaccines through a tough sanctions regime.

While food and medicine are technically exempt, international banks tend to refuse transactions involving Iran.

Russia registered the jab -- named after the Soviet-era satellite -- in August last year, before the start of large-scale clinical trials, leaving some experts wary.

Sputnik V's developers have since said the vaccine is more than 90 percent effective and several countries outside of Russia have begun administering it, including Argentina and Hungary.

German Health Minister Jens Spahn said Wednesday talks were ongoing with Russia to explore production capacities for the Sputnik jab in Germany or elsewhere in Europe.

Iran's Health Minister Saeed Namaki said on Wednesday that Anglo-Swedish firm AstraZeneca would provide the country with 4.2 million doses of its vaccine.

"AstraZeneca is produced in Russia, India and South Korea, and Iran uses these anti-coronavirus products," health ministry spokesman Kianoush Jahanpour told AFP.

They were purchased via Covax, the mechanism for the equitable distribution of vaccines established by the UN World Health Organization.

Iran started clinical trials of its own vaccine in late December.