The growing death toll of a terror attack in Egypt is already four times the scale of the 2016 Orlando nightclub shooting and the 2005 London bombings combined.

Militants killed 305 people, including 27 children, when they detonated explosives and sprayed gunfire at a crowded mosque in the Sinai peninsula of Egypt on Friday.

Survivors said the attackers systematically shot “anyone moving or breathing” in the head or chest, after the initial assault.

Confronting images of the scene show motionless bodies, including those of children, lying in pools of blood and wrapped in makeshift shrouds.

It is the most destructive militant attack in modern Egyptian history.

Worshippers were finishing prayers at the mosque when a bomb exploded. Photo: AAP

In comparison, the Orlando shooting at a gay nightclub in the United States last year and the series of co-ordinated bombings in London in 2005 – two of the deadliest terror events in the Western world in recent years – claimed 77 lives, according to the Global Terrorism Database.

More recently, the high-profile string of terror attacks in the United Kingdom this year accumulated a total death toll of 36 – Westminster (five lives), London Bridge (eight), London mosque (one), Manchester (22) – while the mass shooting in Las Vegas last month killed 58.

This year there have been more than 1000 terror attacks globally, killing about 7000 people.

The consecutive terror events in the UK attracted extensive media coverage by the Western world, however their corresponding death tolls amounted to less than 0.5 per cent of the overall loss felt across the world at the hands of terrorists.

The harrowing news from Egypt failed to feature in leading positions on Western news website homepages or newspaper front pages in the same way terror attacks in the UK and US made headlines.

While media coverage of terror attacks centred on the UK this year, this did not reflect the global terror impact. Photo: Esri.com

Egyptian state media reported that about 40 gunmen set up positions outside the Al Rawdah mosque in Bir al-Abed in the country’s North Sinai on Friday and opened fire from different locations.

They arrived in five SUVs, took positions across from the mosque’s door and windows, and just as the imam was about to deliver his sermon from atop the pulpit, they opened fire and tossed grenades.

A stampede broke out in the rush towards a door leading to the washrooms. Others tried desperately to force their way out of the windows.

“They were shooting at people as they left the mosque,” said a local resident whose relatives were at the scene.

“They were shooting at the ambulances too.”

As worshippers fled the mosque, a bomb was also detonated.

Clad in military-style camouflage pants and black T-shirts, one of the attackers carried a black banner with the declaration of the Muslim faith – there is no God but Allah and Muhammad is his prophet. The banner matched those carried by Islamic State.

A statement by the country’s chief prosecutor, Nabil Sadeq, said the attackers, some masked, numbered between 25 and 30.

More than 50 ambulances reportedly ferried casualties from the mosque to the nearest hospitals.

Prime Minister Malcolm Turnbull condemned the “appalling and barbaric” terrorist attack.

“We send our condolences to the families of the victims and wish a speedy recovery for the injured,” Mr Turnbull tweeted on Saturday.

“We are resolute in our determination to defeat Islamist terrorism and keep Australians safe.”

Egypt’s military responded on Saturday with airstrikes directed at “terrorist” locations.