Citing data from Reuters, the following timeline cites the events that feed the escalated tension among major state players, like US and Iran.

Timeline of events

-2 May: One year after the US withdrew from the JCPOA (Joint Comprehensive Plan of Action), re-imposing nuclear-related sanctions, the US ended waivers that had allowed some mainly Asian importers to continue buying Iranian crude.

-5 May: The US says it is deploying an aircraft carrier strike group and bombers to the Middle East, citing threats from Iran, according to Reuters.

-8 May: Iran announces it will relax some curbs on its nuclear program, stopping short of violating its 2015 deal with world powers, but threatening more action if countries do not shield it from US sanctions.

-10 May: The US Maritime Administration (MARAD) issues a warning that Iran could target US commercial ships, including oil tankers, sailing through key Middle East waterways.

-12 May: The first of the two major attacks is reported with an attack against four ships, including two Saudi oil tankers, in the Gulf just outside the Strait of Hormuz, a major oil shipping route. US officials pin the blame on Iran, a charge Tehran denies.

-13 June: The second attack occurs, involving two tankers attacked south of the Strait of Hormuz. US again blames Iran, but Tehran denies accusations. Meanwhile, oil prices surge by 4% in the next few days.

-20 June: Iranian forces shoot down a US military surveillance drone over the Strait of Hormuz.

-27 June: Royal Marines seize the Iranian supertanker Grace 1 near Gibraltar, on suspicion of violating EU sanctions on Syria.

-5 July: An Iranian Revolutionary Guards commander threatens to seize a British ship unless the Grace 1 is released.

-6 July: The oil tanker 'British Heritage' run by oil major BP is kept inside the Persian Gulf, off Saudi Arabia, in fear it could be seized by Iran for retaliation of the Grace 1 seizure.

-7 July: Iran announces it will boost uranium enrichment above a cap set under the 2015 nuclear deal and will reduce its commitments to the pact, drawing a warning from US President Donald Trump and expressions of concern from Germany, France and Britain.