Stena Bulk is reaching out to Indian Prime Minister Narendra Modi and other countries' top officials for help in securing the release of the seafarers detained by Iran alongside one of its tankers.

The Swedish shipowner said Wednesday that chief executive Erik Hanell has made a "direct appeal" to Modi, along with the foreign affairs ministers of Russia, Latvia and the Phillippines.

"Stena Bulk and Northern Marine Management believe the pressures are growing on both crew and their families and that their immediate release is essential for their well-being," Stena said in a statement.

On 19 July, Iranian Revolutionary Guard commandos seized the 50,000-dwt Stena Impero (built 2018), along with its crew of 23 — 18 of which are Indian — as it transited the Strait of Hormuz. Iran accused the ship of violating international regulations and took it to Bandar Abbas.

The rest of the crew are Russian, Latvian or Filipino.

Stena has said the seafarers are reportedly in good health, but are concerned about when they will be permitted to leave the Islamic republic.

The company has attempted to gain access to the ship and its crew, but Iran has yet to allow any such access.

India maintains economic ties to Iran, with imports totaling $10.25bn, almost all of it crude oil, according to statistics from the Massachusetts Institute of Technology.

It was reportedly one of the reasons why India turned the US down on its invitation to join a military coalition to protect commercial shipping in the strait and the Middle East Gulf.

The 19 July seizure escalated tensions in the politically- and economically-sensitive region further after incidents in May and June saw tankers allegedly sabotaged and the 1 July arrest of a Ukrainian flagged tanker supposedly headed to Syria by the UK in Gibraltar.

The UK has stationed two warships in the region to escort UK-flagged ships.

The UK is also the only country to publicly join US efforts to defend commercial ships.