Iran has executed a former Ministry of Defence official on charges of spying for the United States government.

Jalal Hajizavar, an ex-contract employee for the aerospace arm of the country's defence department, was put to death for secretly working for the CIA, the IRIB news agency reported today.

A military court convicted him after an investigation discovered documents and spying equipment at his home.

Jalal Hajizavar's death comes amid escalating tensions between Washington and Tehran (President Hassan Rouhani pictured)

Over the past weeks the US and Iran's main regional rival Saudi Arabia have also blamed Iran for attacks on two oil tankers last week in the Gulf of Oman and on four tankers off the United Arab Emirates on May 12

President Donald Trump has accused Iran of attacking the tankers, one of which erupted in a fireball on Thursday

He was executed at the Rajai Shahr prison in Karaj, west of Tehran, but it is not yet clear when he was arrested.

His contract with the defence ministry had been terminated during the Iranian year 1389 (March 2010-2011).

Reports state that Hajizavar's ex-wife was also convicted of 'involvement in espionage' and is serving a 15-year jail sentence.

His death comes amid escalating tensions between Washington and Tehran which flared up this week when a US drone was allegedly shot down by the Iranian military.

Today, in what has been interpreted as a veiled threat towards the increasingly aggressive regime, Donald Trump said: 'Hopefully Iran is smart and cares about its people.'

A diagram showing the U.S. and Iranian forces in the region and the location of recent attacks on oil tankers and a Saudi oil pipeline, which have escalated Middle East tensions

The Pentagon flew an MQ-9 Reaper drone like this one over the Gulf of Oman Friday and saw Iranian boats converging on a pair of oil tankers that were later targeted by explosive mines; Iran fired a surface-to-air missile at the drone but missed

The news comes as he announced a trip to the Camp David presidential retreat to consider his next moves against the state.

Tensions in the region began to worsen significantly when Trump pulled out of a 2015 nuclear deal between Iran and six powers and reimposed sanctions on the country.

Over the past weeks the US and Iran's main regional rival Saudi Arabia have also blamed Iran for attacks on two oil tankers last week in the Gulf of Oman and on four tankers off the United Arab Emirates on May 12.