Maersk Line said on Monday it had met again with the Ports & Maritime Organization (PMO) in Iran regarding the seizure of the vessel Maersk Tigris but has yet to receive any official documents from Iranian authorities. The Maersk Tigris was seized last Tuesday by Iranian patrol boats in the Strait of Hormuz, prompting the United States to send vessels to monitor the situation as well as to accompany U.S.-flagged vessels passing through the strait. Maersk said its representative met Iranian PMO officials, while the Danish ambassador in Iran met with officials from the Iranian ministry of foreign affairs. However, little progress appeared to have been made. “We have yet to receive any written notifications (court ruling, arrest order or similar) pertaining to the seizure of Maersk Tigris or the cargo case,” Maersk wrote in a statement. Iran has said the seizure concerns a years-old case over uncollected cargo. Maersk has acknowledged the case but says it has not received the latest documents from a recent ruling. The Maersk Tigris is not owned by the Danish shipping company. Maersk had chartered the vessel, which according to ship operator Rickmer Shipmanagement is owned by undisclosed private investors. Maersk repeated that the crew and the vessel should be released immediately. The incident occurred at a critical juncture in U.S.-Iranian relations, which could thaw should a tentative nuclear deal between Tehran and six world powers including Washington be clinched. It also coincides with heightened tension between regional rivals Iran and Saudi Arabia over the civil war in Yemen, in which they support opposing sides. The Iranian Embassy said in a statement on Thursday the vessel would only be let go once the debt case was settled.