In an interview with Al Jazeera, John Stawpert, marine director of the International Chamber of Shipping, said seafarers must be allowed to carry out their work “freely and without persecution.”

Stawpert, whose organisation represents about 80 percent of the world’s merchant fleet, described the seizures as an affront to freedom of navigation as enshrined in international law. “All these people are doing is transporting trade. We cannot have a situation where ships are being seized, ultimately for political ends, to make a political point,” he said. “These are innocent seafarers, and they should be allowed to do their jobs without fear of, essentially, imprisonment.”

He added that Iran’s stated intention to impose tolls in the Strait of Hormuz has no basis in international law and could set a dangerous precedent. “If this can be done in the Strait of Hormuz, why not in the Strait of Gibraltar or the Strait of Malacca?” he asked.

Stawpert also said that Donald Trump’s naval blockade of Iranian ports has added further uncertainty for shipping companies already grappling with Iran’s effective closure of the strait. “We don’t know what conditions are in place. We don’t know what Iran’s targeting criteria are,” he said. “And now we have another state effectively doing the same thing through a blockade.”

The US and Iranian militaries have each announced the capture of two commercial vessels over the past week, as Washington and Tehran continue to face off in the strait and surrounding waters.

The United States Department of Defense said on Thursday that it had seized the Iran-linked vessel Majestic X while it was transporting sanctioned oil in the Indian Ocean, days after announcing the interception of another ship, Tifani.

Meanwhile, Iran’s Islamic Revolutionary Guard Corps said on Wednesday that it had seized the Panamanian-flagged MSC Francesca and the Greek-owned Epaminondas for “operating without the necessary permits and tampering with navigation systems.”

The Philippines Department of Migrant Workers confirmed that 15 Filipino seafarers were aboard the two vessels. Officials said they had been assured by Iranian authorities that all crew members were “unharmed” and “safe.” (Aljazeera)