Smart Tankers, a Greek ship manager, is still waiting to hear from Iran on why its special forces seized one of its tankers at open sea 15 days ago.

The Piraeus-based company said in a statement on Thursday that it has not been given any explanation for the detention yet.

Mystery continues to surround the motives behind Iran’s interception of the 309,000-dwt Niovi (built 2005), one of three tankers it has seized in Middle East Gulf waters since late April.