Sri Lanka's foreign ministry says it has coordinated efforts to treat and repatriate 40 Iranian sailors suffering from unspecified medical emergencies in international waters off the island's southeastern coast.

Axar.az reports that Ministry spokesperson Thushara Rodrigo told BBC Sinhala they received a distress call on Saturday from Iranian ships "regarding an urgent medical need".

The rescue operation was planned by the Iranian Embassy in Colombo, he said.

Iranian ships have been stranded at sea due to a US naval blockade. Sri Lanka stresses it is neutral in the conflict, but has at times offered help to Iranian sailors in what it says is an obligation to international law.

A BBC Sinhala report last month found that there were 21 Iranian vessels located in international waters near Sri Lanka.

The 40 rescued sailors served on different ships - though Sri Lankan authorities do not have information on how many ships they belonged to, Rodrigo said.

The sailors were brought ashore and taken to Colombo for medical treatment before being sent back to Iran by plane on Saturday night, he added.

He said that several agencies were involved in the operation, including local shipping companies.