Huge crowds have gathered in Cairo after the Muslim Brotherhood called on its supporters to converge on central Ramses Square.

Angry scenes have resulted in clashes between Morsi supporters and the authorities, resulting in dozens of injuries and deaths.

Gunfire rang out over a main Cairo overpass and police fired tear gas as clashes broke out after tens of thousands of Muslim Brotherhood supporters took to the streets.

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Military helicopters circled overhead as armed residents set up checkpoints throughout the capital.

Clashes erupted between Brotherhood supporters and locals opposed to their protest .

Protesters and residents of the neighborhoods exchanged gunfire as tanks blocked key roads and key junctures. The Brotherhood urged its supporters in Cairo to head to Ramses Square, near the capital's train station in the heart of the capital. 

A Health Ministry official speaking on state television said eight people were killed in the city of Dumyat, north of Cairo. Security officials said all the protesters there were killed by live ammunition when they tried to storm police stations.

A protester was also killed near Ramses Square, security officials said.

The Interior Ministry said a total of eight policemen had been killed throughout Egypt.

Chaos: The army has deployed dozens of armoured vehicles on major roads in Cairo, and the Interior Ministry said police will use live ammunition against anyone threatening state installations

The protests were larger and fiercer than in previous weeks, ignited by the outrage over the deaths of at least 638 people on Wednesday when riot police raided two sit-in protests in Cairo by supporters of ousted President Mohammed Morsi.

Soldiers blocked access to the landmark Tahrir Square in Cairo, where dozens of anti-Brotherhood protesters have been camped out for weeks. Barbed wire surrounded the area.

Men carried assault rifles on the overpass leading to Ramses Square. An Associated Press reporter there saw one protester wounded by a bullet in the leg.

It comes as Britons have been confined to their hotel grounds in the Red Sea resort of Hurghada.

Although Germany has advised its nationals not to travel to Egypt, the UK Foreign Office  is saying it is currently not advising against travel to the country's Red Sea resorts.

Also Friday, security officials said assailants detonated explosives on train tracks between Alexandria and the western Mediterranean Sea province of Marsa Matrouh.

There were no injuries and no trains were damaged from the attack, officials said, speaking on condition of anonymity in line with regulations.

Wednesday's assault had triggered daylong running battles and deadly clashes between security forces and Morsi's supporters elsewhere in Egypt. The Interior Ministry later said it authorised the use of deadly force against anyone targeting police and state institutions.

Egypt, the Arab world's most populous nation, has been sharply polarised since the military removed Morsi from power on July 3, following days of mass protests against him and his Brotherhood group.

But Morsi's supporters have remained defiant, demanding the coup be overturned. The international community has urged both sides in Egypt to show restraint and end the turmoil engulfing the nation.

The Brotherhood's political wing, the Freedom and Justice Party, said in a statement today that the group is not backing down and 'will continue to mobilise people to take to the streets without resorting to violence and without vandalism.'

The statement said: 'The struggle to overthrow this illegitimate regime is an obligation, an Islamic, national, moral, and human obligation which we will not steer away from until justice and freedom prevail, and until repression is conquered.'

Separately, the Brotherhood's supreme guide Mohammed Badie, wanted by police for allegedly inciting violence, warned in a statement Friday that removing Morsi was an attempt for the military to take over and establish a 'dictatorship'.

The revolutionary and liberal groups that helped topple Morsi have largely stayed away from street rallying in recent weeks.

British holidaymakers at Red Sea resorts have been confined to their hotels as Egypt lurches closer to civil war.

More than 40,000 UK tourists are in the strife-torn country, most of them at popular beach destinations such as Sharm El Sheikh.

But as the official death toll from Wednesday’s massacre in Cairo passed 500, the Foreign Office upgraded its travel warning to say that local police have advised tourists to remain within their hotel grounds.

A 24-hour curfew was issued on Wednesday between 7pm and 6am in Sharm el Sheikh and people in Hurghada was also told to stay in their hotels.

After this was lifted yesterday morning, the Foreign Office issued this advice today: 'In Hurghada on August 14 there were some violent clashes, in an area away from tourist resorts. One man was killed.

'Hurghada police advised tourists to remain in hotel grounds. We advise you to follow their advice. You are strongly advised to avoid all demonstrations and large gatherings.

'If you become aware of any nearby protests, leave the area immediately. Do not attempt to cross road blocks erected by the security forces or protesters.'

The FCO has also advised against all but essential travel to Egypt, except for the Red Sea resorts. It said that enhanced security measures were in place to protect the resort areas.

Although the resorts are hundreds of miles from the capital, diving trips and excursions have been halted temporarily amid fears that bloody clashes between security forces and supporters of deposed president Mohamed Morsi’s Muslim Brotherhood will spread.

The Brotherhood says the number of casualties from the attack by the military regime on two camps of protesters is far higher than the official toll of 525 dead and 3,717 injured.

The violence continued yesterday as hundreds of Brotherhood members set fire to a government building near Cairo.

President Barack Obama cancelled US joint military exercises with Egypt and strongly condemned Wednesday’s massacre, when the military regime’s troops opened fire on two camps of Muslim Brotherhood protesters.

Mr Obama warned that Egypt had entered a ‘more dangerous path’ but stopped short of suspending $1.3billion in annual US military aid.

‘Our traditional co-operation cannot continue as usual when civilians are being killed in the streets and rights are being rolled back,’ he said.

‘The Egyptian people deserve better than what we’ve seen over the last several days. And to the Egyptian people, let me say: the cycle of violence and escalation needs to stop.’

Britain summoned the Egyptian ambassador to express its ‘deep concern’. The violence in Cairo has triggered a state of emergency and a curfew in several cities.

The Foreign Office says travel advice for Red Sea resorts is unchanged but local authorities in Sharm El Sheikh have temporarily stopped tourist excursions.

‘In Hurghada the police have advised tourists to remain within hotel grounds,’ it adds.

‘We advise British tourists to follow the regulations set by the local authorities and to obey curfews. British tourists should also ensure they keep valid identification with them at all times.’

UK tour operators Thomson and First Choice have 11,769 British holidaymakers in Egypt, many of them in Sharm el Sheikh.

A spokesman for the two companies said: 'We are working with the FCO and monitoring the situation closely in Egypt.

'The majority of our customers are in Sharm el Sheikh which is a considerable distance - indeed, an eight-hour drive - from Cairo. There have been no related incidents in Sharm el Sheikh or any of the other popular Red Sea tourist areas.

'Like much of Egypt, Sharm el Sheikh was subject to an evening curfew until 6am yesterday morning. This has now been lifted and all our excursions in the Red Sea resorts will resume from today.'

Thomas Cook said the Red Sea resorts were ‘operating as normal, bar an evening curfew in Sharm El Sheikh that was observed on August 14.

‘Our experienced teams on the ground have confirmed that no tourist areas have been further impacted and that our customers continue to enjoy these popular Red Sea resorts.’

The firm added that it has cancelled excursions from the resorts to Cairo, Luxor, Moses Mountain and St Catherine’s Monastery but ‘some excursions for UK customers will be operating again as of August 16 within the perimeter of Sharm El Sheikh.

These include boat and diving excursions, quads and city tours.’ 

In light of the Foreign Office travel advice, Thomson Cruises has changed its itinerary for an Egypt & the Holy Land voyage on the Thomson Celebration vessel starting next Monday.

The company said: 'All customers set to travel on Monday are being proactively contacted by our dedicated customer team and advised of this change.

'We understand this news will be disappointing for Thomson Cruise customers set to travel on this itinerary, but these circumstances are out of our control and we are doing everything possible to minimise the disruption to customers.'

The violence has left Egypt facing another sharp fall in tourism, which has already suffered a severe decline since the 2011 revolution that toppled President Hosni Mubarak.

ABTA, which represents British estate agents, said: 'ABTA and our members continue to monitor the situation in Egypt and follow advice from the Foreign Office which states that  the Red Sea resorts have not been affected by the recent demonstrations and remain safe to travel to.

'As a sensible precaution the Egyptian authorities declared a curfew in Sharm El Sheik between the hours of 7pm and 6am on 14 August, this has subsequently been lifted.'