Three Egyptian judges have been shot dead hours after deposed former president Mohamed Morsi was sentenced to death.

Police said the judges were travelling in a car in the city of al-Arish, Sinai, when it was attacked by suspected Islamist gunmen.

An fourth person was killed and at least three more were injured in the assault.

A militant believed to support Mohamed Morsi during attacks on security forces in al-Arish after he was deposed in August 2013 (EPA)

It is unclear whether the attack was linked to anger over the death sentence passed for Mr Morsi in Cairo but the Egyptian government has blamed Muslim Brotherhood supporters for violence in Sinai in the past.

Mr Morsi's party has been banned and hundreds of its former officials and supporters have been arrested and jailed.

Egypt's interior ministry said a policeman was also killed on Saturday in the outskirts of Cairo by gunmen on motorcycles.

The shootings came days after another judge was the victim of an assassination attempt.

Al-Arish is just 30 miles from the Rafah crossing between Egypt and the southern Gaza Strip (Getty Images)

Moataz Khafagi, who sentenced 12 Muslim Brotherhood members to death last year after convicting them of killing a police general, survived bomb blasts outside his home in Cairo suburb that damaged several cars but caused no casualties.

The Sinai Peninsula has seen frequent outbreaks of violence in recent months and terrorist attacks prompted the Egyptian government to declare a state of emergency last year.

In January, an Isis-affiliated group claimed responsibility for rocket and bomb attacks on the military and police that killed at least 26 people.

The Foreign and Commonwealth Office (FCO) has raised concern about the deteriorating situation and advises against all travel to North Sinai, where al-Arish is situated.

President Al-Sisi called three days of national morning mourning following attacks in the Sinai Peninsula last year

“Terrorists and criminals seek to prevent the Egyptian authorities from exercising control,” a spokesperson said.

“There are regular bomb attacks against government buildings, security forces and energy infrastructure.

“The al-Arish area has seen many attacks, but the whole of the North Sinai region is at risk.”

The Egyptian army are fighting militants in the area and several hundred people are believed to have died in battles since July 2013, when security forces were attacked by people angry at the coup against Mr Morsi.

In pictures: Egypt protests on Arab Spring anniversary Show all 11 1 /11 In pictures: Egypt protests on Arab Spring anniversary In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests A supporter of Egyptian President Abdel Fattah al-Sisi waves his national flag during a demonstration in Cairo on January 25, 2015 AFP In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests A riot police officer holds a weapon during an anti-government protest in downtown Cairo January 25, 2015 Reuters In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests An anti-government shouts slogans against the military and interior ministry during a protest in front of the journalists' syndicate in Cairo January 25, 2015 Reuters In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests Anti-government protesters shout as they call out to others with them to walk into Tahrir square after they clashed briefly with pro-government protesters, in Cairo January 25, 2015 Reuters In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests Anti-government protesters help an injured protester when pro-government protesters threw stones during a protest in front of the press syndicate in Cairo January 25, 2015 Reuters In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests An Egyptian is arrested by plainclothes police in downtown Cairo, Egypt, Sunday, Jan. 25, 2015 AP In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests Egyptian security forces deploy in the Cairo suburb of Matariyah, Egypt, Sunday, Jan. 25, 2015 AP In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests A woman mourns during the funeral of Shaima al-Sabbagh, Alexandria, Egypt, 25 January 2015 EPA In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests Two supports of ousted President Mohamed Morsi in front of security forces near Tahrir Square in Cairo (AFP) In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests Egyptian policemen detain a supporter of the People's Alliance Party during a demonstration in Cairo's Talaat Harb square, near Tahrir square, on January 24, 2015 (AFP) In pictures: Egypt protests on Arab Spring anniversary Cairo anniversary protests People carry the coffin of Shaima al-Sabbagh during her funeral, Alexandria, Egypt, 25 January 2015 EPA

Sinai borders the Gaza strip and Egyptian state prosecutors have claimed that Mr Morsi colluded with the Palestinian Hamas group while his predecessor was being overthrown during the Arab Spring.

They alleged that during the 18-day uprising in 2011, militants passed through illegal tunnels between Gaza and Sinai to enter Egypt and help hundreds of Muslim Brotherhood supporters, including Mr Morsi, escape jails in the capital in violent prison breaks.