Major buyers are picking bigger volumes before the latest US sanctions waivers expire in early May," ISNA quoted shipping sources as saying.
According to the news agency, oil exports plunged under the US restrictions announced last May. Nonetheless, levels recovered to some extent in March. The National Iranian Oil Company exported close to 2.6 million bpd last May.
Exports are likely to decline again in the coming months if the US mounts pressure on the main oil buyers including China, India, Japan, South Korea, Turkey and Greece.
Most market observers including Sara Vakshouri, president of SVB Energy International in Washington DC, expect at least four of Iran's top crude and condensate buyers -- China, India, Turkey and South Korea -- to get extension of US waivers.
"They are likely to be granted one, although exemptions for Italy, Greece, Japan and Taiwan are bound to halt," ISNA reported.
The US administration seems to be committed to "zeroing out" Iranian oil exports, but energy analysts remain skeptical that exports would fall to this figure.
"We do not see Iran oil exports to reach zero. Such a scenario will pose real threats against the security of oil flow from the Persian Gulf," said Vakshouri. She did not elaborate.
She estimated Iran's oil exports to average 470,000-500,000 bpd if only China, India and Turkey receive exemptions. "If Japan and South Korea also succeed to receive Iran oil import waivers, Iran oil export may amount to 670,000-850,000 bpd," she added.
Data from Ursa, a geospatial analytics startup, which tracks oil inventories using satellite data, shows that Iran's crude inventories have fallen by almost 25% since early January, led by Kharg Island, the country's main export terminal, which witnessed a 30% fall in March.
Iran produced 2.69 million bpd of crude in March, according to the recent S&P Global Platts OPEC Survey, a fall of 280,000 bpd from November.
India received a US waiver to continue buying Iranian oil, at a rate of around 300,000 bpd. Although not all Indian refiners continued purchases, India used up its 300,000 bpd quota allowed under the exemption.
According to data obtained by Reuters, India’s imports of Iranian oil jumped to 405,000 bpd in March up 56% from a month earlier.
India is not booking Iranian oil in May as refiners are waiting for more clarity from the US on whether India will get its sanctions waiver extended.