It is understood that jihadists in Syria have breached the British ministerial email system in a cyber espionage operation to intercept sensitive emails.

The UK Government Communications Headquarters (GCHQ), an intelligence agency, discovered that extremists affiliated with the Islamic State and the Levant (ISIL) have been actively targeting information communicated by Britain’s most senior ministers, the Telegraph reports.

According to insiders at GCHQ, the email system was not entirely breached but they confirmed that hackers gained access and read multiple emails.

So far, only Theresa May, the Home Secretary has been confirmed as a victim of the hacking incident but it is highly likely that other senior ministers from UK Prime Minister David Cameron’s staff are compromised as well.

Intelligence officials believe that the hacking extremists may have learned about events that were to be attended by members of the Royal family and other prominent government figures.

The news comes less than a fortnight after US officials announced that Junaid Hussain, 21, a “top cyber jihadist” had been killed in Syria by a US military drone strike.

The hacker was believed to be the brains behind ISIL’s hacking operation, operating a jihadist cyber group calling itself the Cyber-Caliphate. The group recently took control of a Pentagon-owned Twitter account briefly in January.

Hussain was also jailed for six months in 2012 after initiating a computer hack that breached former UK Prime Minister Tony Blair’s electronic diary.

“We need to maintain vigilance and good intelligence to stop future plotting, and ultimately we must destroy the group’s terrorist sanctuary,” said Michael McCaul, chairman of the US Homeland Security Committee.

Last week, reports emerged that a British jihadist was killed in Syria by UK forces after the revelation that he had directed a plot to kill the Queen.

The Islamic State is known to undertake aggressive recruiting campaigns via social media, and more specifically – Twitter.

Twitter has since responded by terminating tens of thousands of social accounts related to the militants in recent months.