Terror manuals outlining how to make bombs and use firearms effectively are being circulated by British extremists online.

The interactive guides, which encourage 'lone wolf' attacks, were compiled by a militant from England who claims to have links to ISIS.

They include step-by-step instructions on how to make car bombs 'Iraqi style' and a piece on staying anonymous while using a smartphone.

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Terror manuals outlining how to make bombs and use firearms effectively are being circulated by British extremists online

One, titled the Book of Terror, contains a video of the murder of Fusilier Lee Rigby, who was killed while off-duty near the Royal Artillery Barracks in Woolwich in 2013.

It also features a clip of the 7/7 London terror attacks, which left 52 dead and more than 700 people injured.

All of the manuals contain the strapline: 'A guide to strike terror in the hearts of the kuffar [non-believers] of the West.'

Islamic State has recently renewed calls to its members to carry out more attacks during the month of Ramadan.

According to text, the guides include workouts and weapons training including posture tips when holding a gun

The release of the pamphlets comes after 38 people - including 15 Britons - were killed in Sousse, Tunisia, on Friday after Seifeddine Rezgui (pictured) opened fire on a beach

Witnesses said the 23-year-old also threw a number of grenades, both in the lobby and in the area outside

The release of the pamphlets comes after 38 people - including 15 Britons - were killed in Sousse, Tunisia, on Friday after a gunman opened fire on a beach.

Seifeddine Rezgui, 23, posed as a swimmer before targeting tourists with a rifle.

After leaving the beach he continued shooting at nearby hotel Imperial Marhaba. Witnesses said he also threw a number of grenades, both in the lobby and in the area outside.

While not thought to have a criminal record, the gunman was known to the authorities for his ‘low-key radical behaviour’, according to Tunisian Interior Ministry source.

The UK government has so far not altered its travel advice for Tunisia in the wake of the attack.

The official guidance states: 'A terrorist attack took place at Port El Kantaoui near Sousse on 26 June.

'A number of foreign tourists were killed, including British nationals. The incident is over. A reinforced British Embassy team is on the spot providing consular assistance to British nationals.'

But it adds: ‘Further terrorist attacks in Tunisia, including in tourist resorts, are possible, including by individuals who are unknown to the authorities and whose actions are inspired by terrorist groups via social media.'

Friday's attack in the north African country came just hours after an ISIS fanatic beheaded a man at a factory in France. Above, an image of the scene after

Friday's attack in the north African country came just hours after an ISIS fanatic beheaded a man at a factory in France.

Herve Cornara's head was found pinned to the gates at the American-owned Air Products factory in Saint-Quentin-Fallavier. It was surrounded by two Islamist flags.

Four people were held in custody in connection with his beheading and for setting off the explosion at the Air Products gas factory in south-eastern France.

The attacks prompted Teresa May to state on Sunday morning that parents should report their children to the police if they are at risk of becoming terrorists.

The Home Secretary said it was difficult for the intelligence agencies and police to stop so-called ‘lone wolf’ attacks launched by individuals who have been radicalised online.

She also revealed plans for a major counter-terror exercise to 'test' the country’s ability to deal with an attack on British soil.