Open-source flight-tracking data showed a US Air Force aerial refuelling aircraft that had departed Tel Aviv transiting airspace over the United Arab Emirates, hours after Iran warned over the movement of Israeli military aircraft towards its territory, Flightradar24 data showed on June 26.

The flight comes at a tense moment in the period since the war, with a fragile ceasefire holding and Iran signalling it will treat military air activity near its borders as a threat, even as the United States and Iran pursue a 60-day process to implement the memorandum of understanding that ended the fighting.

The aircraft, a Boeing KC-135R Stratotanker registered 57-1512 and listed as military or government, was tracked over the UAE near Ras Al-Khaimah at an altitude of 27,000 ft, on a heading of 110° and a ground speed of 416 knots, having departed Tel Aviv.

The KC-135R is an aerial refuelling tanker rather than a strike aircraft, and the airframe was US-registered, not Israeli.

The data emerged after Iran's IRGC Khatam al-Anbia Central Headquarters, the country's top operational military command, warned over what it described as the movement of Israeli military aircraft towards Iran.

The command said the movements and presence of military aircraft belonging to the Israeli army in the skies of some neighbouring countries heading towards Iran were a dangerous act and a threat against the Islamic Republic.

The headquarters said that if the United States was unable to rein in and control Israel, Iran would not tolerate any threat against it and considered responding to such acts its right.

The warning did not identify any specific aircraft, type or registration, and the flight-tracking data does not establish a link between the US tanker and the movements the Iranian command referred to.

A second US tanker was recorded as heading towards the Iranian island of Kish at 09:26 BST. 

Iran and the US—including Israel—reached a ceasefire on April 8, brokered by Pakistan, which has come under repeated strain.

Israel and Hezbollah have continued to exchange strikes despite a separate ceasefire on the Lebanon front, and Iran has cited what it calls Israeli violations in Lebanon as grounds for keeping the Strait of Hormuz effectively closed.

The United States maintains a significant military presence across the Gulf, including the Fifth Fleet in Bahrain, and US tanker, surveillance and transport aircraft operate routinely across regional airspace.

The US-Iran process, mediated by Pakistan and Qatar, is due to resume at expert level next week, with the two sides working to implement the memorandum and establish a direct communication line between Tehran and Washington to prevent incidents.