The owner of a British tanker seized by Iran in the Strait of Hormuz has raised concerns about the safety of the crew still on board. The company has been in telephone contact with the crew, but it has not been allowed to visit the 23 sailors aboard the impounded <em>Stena Impero</em>. "We are concerned about the potential impact a prolonged period of uncertainty will have on the welfare of both crew and their families," said Stena Bulk, the shipping unit of Sweden's Stena AB. Iran's Islamic Revolutionary Guard Corps is holding the <em>Stena Impero</em> and 23 crew members it detained on July 19. The move came after UK forces seized an Iranian tanker near Gibraltar for allegedly breaching sanctions against Syria. The UK has threatened "serious consequences" if the ship and its crew are not released but new Foreign Secretary Dominic Raab said on Monday that he would not consider releasing the <em>Grace 1</em> in exchange for the <em>Stena Impero</em>. On Monday, Stena Bulk said there was no evidence to suggest the tanker breached any maritime rules or regulations. "Our colleagues on the <em>Stena Impero</em> were carrying out their profession as merchant seafarers and do not deserve to be in this position," it said. Meanwhile, the United States is pushing ahead with a plan to deploy an international coalition of warships to safeguard traffic through the vital Strait of Hormuz. Secretary of State Mike Pompeo said that the plan would take time but he was confident "countries from all across the world who have a vested interest in keeping those waterways open will participate". He said “it will take more time than we wish it would take, but I’m very confident that the world understands its importance … America is prepared to be a significant part of that, but we need countries from all across the world to assist us in protecting commercial transit”. US officials have written to the German government requesting it joins France and Britain in providing security for tanker traffic through the Straits of Hormuz, the embassy in Berlin said on Tuesday.<br/> <br/> "We've formally asked Germany to join France and the UK to help secure the Straits of Hormuz [sic] and combat Iranian aggression," embassy spokeswoman Tamara Sternberg-Greller said.<br/> <br/> "Members of the German government have been clear that freedom of navigation should be protected," she said. "Our question is, protected by whom?" Iran's seizure of the British-flagged Stena Impero and the Panama-flagged MT Riah in the Strait of Hormuz - a strategic shipping route between Iran and Oman - prompted Britain to propose a maritime security mission to the region.<br/> <br/> Tensions in the Gulf spiked after British Royal Marines assisted in capturing the Iranian tanker off Gibraltar in early July. London had said it believed the vessel was transporting oil to Syria in violation of EU sanctions on the regime.<br/> <br/> Several EU member states have expressed interest in the mission to ensure safe travel of cargo but Berlin has all but ruled out a naval contribution.<br/> <br/> Diplomats in Brussels have aid countries including Denmark, Poland, Portugal, Spain and Sweden have expressed interest. France is also thought to be in favour, although Paris has yet to agreed the details of a deployment.<br/> <br/> While Britain appears likely to join the US convoy coalition, it has not abandoned its hopes for a European-led initiative.<br/> "We continue to work with all our international partners and aim to bring together as many nations as possible to protect shipping lanes in the Gulf," the British government said in a statement on Tuesday. The US call puts countries like Japan in a difficult position. Tokyo is a major buyer of Middle Eastern oil and has a vested interest in securing maritime traffic through the region. But despite being a strong US ally, Prime Minister Shinzo Abe also has to balance the views of voters suspicious of overseas deployments. The stakes are high for Mr Abe's government, which has described safe shipping through the Strait of Hormuz as a "matter of life and death in terms of energy security". Japan gets 80 per cent of its crude imports from the Middle East, much of it through the choke point at the focus of recent tanker attacks. The US has imposed sanctions on Tehran since it withdrew from the 2015 nuclear accord last year and countries like Japan have cut their purchases of Iranian oil in response. The US blames Iran for attacks on several tankers in recent months in the Gulf region and the move to impound the <em>Stena Impero</em> has also concerned traders. BP has not taken any of its oil tankers through the Strait of Hormuz since a July 10 attempt by Iran to seize one of its vessels, the British company's chief financial officer Brian Gilvary said on Tuesday. Mr Gilvary also said the company had no plans to take any of its vessels through the strait but would continue to ship oil out of the region on chartered ships. "We will continue to make shipments through there but you won't see any BP-flagged tankers going through in the short term," he said. In new video and audio released on Monday, an IRGC officer is heard telling a British warship not to interfere or put their "life in danger" as the paramilitary force, using speedboats and a helicopter, seizes the <em>Stena Impero</em>. The video includes a shot, apparently filmed on the day of the July 19 incident, from above the British warship <em>HMS Montrose</em>, call sign Foxtrot 236, that was in the vicinity of the UK-flagged vessel. The shot shows the British navy unable to prevent Iran's seizure of the ship. It also offers new glimpses into the tense exchange that took place between the Royal Navy and the IRGC navy during the seizure. In the nearly two-minute video released by IRGC, an officer is heard telling the British warship: "You are ordered to not interfere in my operation." The Iranian officer repeats: “You are required not to interfere in this issue.” In response, a British officer responds: “This is British warship Foxtrot 236. I am in vicinity of the internationally recognised strait with a merchant vessel in my vicinity conducting transit passage.” The Iranian officer is then heard saying: “Don’t put your life in danger.” He is also heard saying the commercial ship is under Iranian control. The audio appeared to have been edited, leaving out parts of the exchange released last week by London company Dryad Global, in which a British officer is heard telling the Iranian forces they must not impair, impede or obstruct the passage of the <em>Stena Impero</em> in a recognised international strait. Th IRGC had previously released video of the incident showing Iranian commandos in black ski masks and fatigues rappelling from a helicopter on to the ship. The latest video and audio come only days after the UK's <em>HMS Duncan</em>, a new Type-45 destroyer, joined the <em>HMS Montrose</em> in the region. The two warships will defend freedom of navigation until a diplomatic resolution is found to secure the waterway. The HMS Duncan is scheduled to replace the <em>HMS Montrose</em>, so it is not clear how long the UK will keep both vessels in the region. Iranian officials have alleged the <em>Stena Impero </em>was seized after it violated international maritime. Iranian officials have also suggested the ship was seized in response to Britain's role in impounding the Iranian supertanker two weeks earlier. Both sides have called the interception of each other's ships "hostile acts" and "piracy". Meanwhile, an Iranian ship called <em>Bavand</em>, which had been at the heart of a geopolitical spat between Brasilia and Tehran, set sail from Brazil on Monday after receiving fuel from state-run Petrobras, the port of Paranagua said. A second Iranian ship, the <em>Termeh</em>, which set sail from Paranagua two days ago, was on Monday heading to the southern Brazilian port of Imbituba, where it is due to pick up a shipment of corn before heading back to Iran. The ships were stranded after Brazil's state oil company refused to sell them bunker fuel because of US sanctions against Iran. Petrobras eventually relented in the face of a supreme-court ruling. The ships' departures mark the end of a longstanding impasse. The Iranian vessels had been at the port of Paranagua for more than 50 days, said law firm Kincaid Mendes Vianna, which represents the company that chartered the ships. The vessels are due to return to Iran carrying 100,000 tonnes of corn worth about $26.5 million (Dh97.3m).