May 12
Four commercial tankers are attacked in the Gulf of Oman. Two Saudi, a Norwegian and an Emirati-registered ship involved in the incident that the US quickly blamed on Iran. Tehran denied involvement and an international investigation is quickly launched.
June 13
The Japanese Kokuka Courageous and the Norwegian Front Altair damaged by limpet mines. The US again blames Iran and releases footage they say shows Iran guards removing an object from the side of one of the ships after the initial blasts.
June 17
The US says Iran shot down a Reaper drone during Gulf of Oman incident.
July 4
British marines seize Iranian Panama-flagged Grace 1 off Gibraltar saying the vessel was transporting oil to Syria in contravention of EU sanctions. Iran demands the return of the ship and warns of repercussions for the action.
July 11
A British naval frigate warned off three Iranian vessels after they attempted to stop and divert an oil tanker from its passage through the Strait of Hormuz.
July 13
Panama flagged Riah shuts off tracking systems and goes dark. Last seen heading towards Iranian waters from Strait of Hormuz.
July 16
US military general says concerned that Iran has seized the Riah. Meanwhile, UAE officials say the ship is neither owned nor operated by the UAE and has no Emirati nationals aboard. UAE officials add that they received no distress signal when the ship went missing.
July 17
Iran says it has towed the Riah to Iran for repairs after receiving a distress signal.
July 19
Hours after the US say they shot down an Iranian drone over the Strait of Hormuz, Iran Revolutionary Guards seize Swedish owned, British flagged tanker Stena Impero.
July 20
The UK demands the return of Stena Impero and British Foreign Minister Jeremy Hunt speaks to Iranian Foreign Minister Mohammad Javad Zarif to express disappointment at the move after Iran said they wanted to de-escalate the situation.
