Iran has sent five planeloads of food to Qatar, which is suffering shortages amid a regional blockade.
A number of nations, including Iran's major rival Saudi Arabia, last week cut ties with Qatar, accusing it of funding terrorism, charges it denies.
The land border with Saudi Arabia, through which 40% of Qatar's food comes, has been closed.
Meanwhile, mediators Kuwait said that Qatar was ready to listen to the "qualms" of its neighbours.
A spokesman for Iran Air, Shahrokh Noushabadi, told the Agence France-Presse news agency on Sunday: "So far five planes carrying perishable food items such as fruit and vegetables have been sent to Qatar, each carrying around 90 tonnes of cargo, while another plane will be sent today."
It is unclear whether the food is an aid delivery or a commercial transaction.
Mr Noushabadi said deliveries would continue "as long as there is demand".
AFP also quoted the Tasnim news agency as reporting that three ships with 350 tonnes of food were also set to leave for Qatar.
Iran has also opened its airspace to Qatari flights, following airspace closures by Saudi Arabia, Bahrain and the United Arab Emirates.
Analysts say Qatar's positive relations with Shia-led Iran - Sunni-ruled Saudi Arabia's arch-rival for influence in the region - were one of the causes of the latest rift, and the latest shipments are unlikely to ease the tension.
Kuwait has taken on the role of mediator, last week sending its emir to Saudi Arabia.
On Sunday, Kuwait's Foreign Minister Sheikh Sabah al-Khalid al-Sabah said Qatar was ready "to understand the reality of the qualms and concerns of their brothers and to heed the noble endeavours to enhance security and stability".
UAE Minister of State for Foreign Affairs Anwar Gargash tweeted: "Is this the beginning of wisdom and reasonable thinking? I hope so."
Qatar separately said it would not retaliate with similar measures after Saudi Arabia, Bahrain and the UAE last week ordered all Qatari citizens to leave within 14 days.
Some 11,000 people from the three nations are believed to be in Qatar.
In other developments on Sunday:
- Saudi Arabia, Bahrain and the UAE have set up hotlines to help families in their countries that have Qatari members. It is the first significant move to lessen the humanitarian impact of the blockade and followed a call on Friday by US Secretary of State Rex Tillerson for measures to be eased
- Qatar has hired former US attorney general John Ashcroft to fight its corner in the international arena
- Fifa president, Gianni Infantino, said he was confident the "region will return to a normal situation" and the current crisis would not affect the staging of football's World Cup in Qatar in 2022
- Qatar's overseer of charities. the Regulatory Authority for Charitable Activities, denied any involvement in funding militants, saying it "deplores the accusation that Qatari humanitarian organisations support terrorism"