An al-Qaida-inspired group based in the Egyptian Sinai threatened Thursday to attack contractors and workers involved in the construction of a security wall at a town in the restive peninsula.

The Ansar Beit al-Maqdis (Partisans of Jerusalem) group has claimed most of the deadliest attacks in Egypt since the military ousted Islamist president Mohamed Morsi in July, saying they were in revenge for a crackdown on his supporters that left hundreds dead.

The United States vowed Thursday it was not backing any particular candidate in upcoming Egyptian elections, with Army chief Abdel Fattah al-Sisi strongly favored to win.

Sisi's candidacy is being hailed by the millions of Egyptians weary of more than three years of turmoil since the overthrow of veteran strongman Hosni Mubarak.

Abdel Fattah al-Sisi is assured of winning Egypt's forthcoming presidential vote but at the cost of reviving the era of strongman rule as he faces a dilapidated economy and rising militancy.

Analysts say Field Marshal Sisi, who on Wednesday announced he was quitting the army to run for president, was certain to continue the crackdown on Islamists that started when he overthrew elected president Mohamed Morsi in July.

Italy's navy said Thursday it had rescued 128 migrants from Egypt, Eritrea, Sudan and Syria from a boat crossing the Mediterranean which got into difficulty off the coast of Sicily.

The migrants, including eight women and 13 minors, were spotted by a helicopter patrolling the seas off Italy on Wednesday as part of an operation launched after two October shipwrecks in which hundreds drowned.

U.S. Secretary of State John Kerry urged Egypt Wednesday to overturn a court decision sentencing 529 supporters of ousted president Mohamed Morsi to death, warning it sent a "negative message" around the world.

"I am deeply, deeply troubled by the sudden and unprecedented decision by an Egyptian court to issue preliminary death sentences for 529 citizens after a quick mass trial," Kerry said in a statement, issued while he was on a surprise trip to Jordan.

Egypt's army chief Abdel Fattah al-Sisi said Wednesday he had he quit the military to run for president, in a widely anticipated move almost nine months after he toppled the elected leader.

Sisi, who was also defense minister, faces no serious competition in the upcoming election, likely before June, and is expected to easily win the poll riding on a wave of popularity.

The internal and regional conditions are “suitable” for holding the presidential elections, president Michel Suleiman assured on Wednesday.

"The rotation of power is a sign of stability,” Suleiman told the Egyptian state news agency MENA, after holding talks with Egypt's Coptic pope Tawadros II at the Baabda Palace.

One person was killed and 14 wounded Wednesday when police and student supporters of Egypt's deposed president Mohammed Morsi clashed at Cairo University, the health ministry said.

Riot police fired volleys of tear gas from the university's main gate at students who were demonstrating against Monday's sentencing of 529 Morsi supporters to death in the biggest such act in the country's modern judicial history, an Agence France Presse correspondent reported.

Gaza's Islamist rulers Hamas announced Wednesday that the blockaded territory's border with Egypt would open after a 50-day closure, telling Palestinians wishing to travel to present their passports.

Egypt has severely restricted access through the crossing in the border city of Rafah since July, when the army deposed Hamas's ally, President Mohammed Morsi of the Muslim Brotherhood.

Two Palestinians were wounded on Wednesday when Israeli navy vessels destroyed two Gaza-bound boats smuggling cigarettes and tobacco from Egypt, Palestinian and Israeli sources said.

Palestinian witnesses and medical sources said the navy opened fire at the vessels as they were heading towards Rafah, moderately wounding two people, while the rest of the crew managed to escape.