An Egyptian army officer was killed on Friday in the collapse of a tunnel in the restive Sinai Peninsula on the border with the Gaza Strip, security sources said.

Another officer was injured in the accident which occurred as the armed forces were trying to blow up the tunnel in the border town of Rafah.

Libya's internationally recognized premier threatened new air strikes with Egypt against the Islamic State group in his country, warning Friday that the jihadists were poised to widen their presence there.

Abdullah al-Thani was referring to February 16 air strikes on the IS stronghold of Derna after the group released a video showing the beheading of 21 Coptic Christians, mostly Egyptians.

More than 25,000 Egyptians have returned from neighboring Libya since the Islamic State group posted a video earlier this month of the beheadings of Christian compatriots, the foreign ministry said Friday.

Egypt carried out air strikes against jihadist targets in Libya on February 16 in retaliation for the executions of the 21 Copts and urged its large expatriate workforce to head home for their own safety.

The Emir of Qatar said Thursday he was committed to "stability" in Egypt, despite a recent row between the two nations over Cairo's airstrikes against IS militants in Libya.

Islamic State jihadists released a video this month showing the beheading of 21 Coptic Christians in Libya, most of them Egyptian, prompting Cairo to launch air strikes on IS targets in the eastern city of Derna.

Prominent human rights lawyer Amal Clooney lashed out at the Canadian government on Thursday, accusing Ottawa of "woefully inadequate" efforts to secure the repatriation of Al-Jazeera journalist Mohamed Fahmy from Egypt.

In a scathing rebuke of Prime Minister Stephen Harper's government, Clooney said diplomats had made only "sheepish whimpers" to Cairo instead of the required concerted efforts to secure her client's return.

Egypt's prosecution service Thursday ordered the arrest of two policemen accused of torturing and beating to death a lawyer jailed after a pro-Islamist protest, state media and lawyers said.

The victim, Karim Hamdi, "was arrested on Monday, referred to the prosecution on Tuesday and on Wednesday his lawyers found out he was dead," Malik Adli, a lawyer who represents protesters, told Agence France-Presse.

One person was killed Thursday in a bombing outside a pizzeria in the Egyptian capital as other blasts hit a police station and offices of cell phone companies, a health official said.

The bomb tore off the legs of the victim who was pronounced dead in hospital, health ministry spokesman Hossam Abdel Ghaffar told AFP. Two other people were wounded.

Egypt's Constitutional Court said it will rule Sunday on whether the electoral law is constitutional, with polls for a new parliament next month likely to be delayed if the decision is negative.

The election, currently set to be held between March 21 and May 7, would be the first since army chief Abdel Fattah al-Sisi overthrew Islamist Mohamed Morsi in 2013.

An Egyptian court set May 16 for a verdict in the prison break trial of ousted president Mohamed Morsi, who could be sentenced to death if convicted, an official said Wednesday.

Morsi, overthrown in 2013, faces several trials along with top leaders of his Islamist Muslim Brotherhood movement.

Egypt said on Wednesday its premier football league, suspended after a deadly stampede and clashes at a Cairo stadium, will resume but no fans will be allowed to attend.

The government suspended the league after 19 people were killed on February 8 when police fired tear gas and birdshot at fans trying to force their way into the stadium, leading to a stampede.