Austria and Greece have emerged as new channels in diplomatic efforts to break the deadlock between the United States and Iran, with both countries' foreign ministers speaking to Iran's top diplomat shortly after meeting or talking with US Secretary of State Marco Rubio.

The contacts came as Washington and Tehran remained at odds over the future of the Strait of Hormuz, a crucial oil-shipping route that has been effectively closed during the conflict. The US administration has denied asking either European government to mediate, but the timing of the conversations has fuelled speculation about a broader diplomatic push.

Rubio met Austrian Foreign Minister Beate Meinl-Reisinger in Washington on Tuesday, 11 August, and spoke by telephone with Greek Foreign Minister George Gerapetritis the following day. Both ministers then held calls with Iranian Foreign Minister Abbas Araghchi on Thursday, according to the Associated Press.

The US State Department said it could not comment on why the European ministers chose that timing and maintained that Rubio had not asked either of them to contact Iran or carry messages to Araghchi. It nevertheless acknowledged that Iran was discussed during Rubio's conversations with both ministers.

An unnamed European diplomat told the Associated Press that the timing was not accidental. Analysts quoted by the agency cautioned, however, that the new contacts should not necessarily be described as formal mediation.

“While the calls to both sides may entail encouraging both Iran and the U.S. back to the negotiating table, such efforts fall short of mediation,” said Mona Yacoubian of the Center for Strategic and International Studies. She said formal mediation requires trust between the intermediary and both sides.

Austria has a particular connection to the nuclear side of the dispute. Vienna hosts the International Atomic Energy Agency, which has long played a central role in monitoring Iran's nuclear programme, and the Austrian capital hosted the final negotiations that produced the 2015 nuclear agreement. IAEA records confirm that key Iran-related negotiations and agreements were conducted in Vienna, including the 2015 roadmap signed there.

Greece, meanwhile, has substantial maritime interests. Its foreign ministry said Gerapetritis was briefed by Araghchi on regional developments and the ongoing discussions concerning the Strait of Hormuz, while stressing the importance of freedom of navigation and maritime security.

Austria's foreign ministry said Meinl-Reisinger offered Vienna as a possible venue for further talks and stressed the need to restore regional stability through diplomacy. It said Austria's priority was safeguarding freedom of navigation through Hormuz.

Iran presented the conversations differently. Its foreign ministry said Araghchi discussed mechanisms for the future management of the Strait with his European counterparts and accused Washington of violating the interim agreement reached in June.

The diplomatic activity comes as the dispute over Hormuz continues to carry major economic consequences. Before the war, the waterway handled roughly a fifth of global oil supplies. Reuters reported on 14 August that only two vessels crossed the strait that day, with no crude oil shipments visible, compared with more than 130 vessels a day before the conflict.

Araghchi said on Saturday that Iran had not yet decided whether to resume talks with Washington and that US conditions concerning the strait would have to be addressed before shipping could return to normal. Reuters reported that the June agreement intended to end the war was effectively in tatters.

The latest European contacts therefore come at a moment when the diplomatic window remains uncertain, while the practical pressure created by the disruption of Hormuz continues to grow.