A series of attacks in Egypt's restive Sinai peninsula over the past 24 hours, mostly against soldiers, killed at least four people, security officials said on Tuesday.

The violence comes as the Egyptian military presses its campaign in Sinai to quell an insurgency that surged after the army overthrew Islamist president Mohammed Morsi on July 3.

Egypt's military says it has seized caches of weapons in a Sinai operation including a mortar apparently belonging to the Palestinian Islamic Jihad group in neighboring Gaza.

The military has launched a sweeping offensive in the north of the peninsula to quell an Islamist militant insurgency that surged after the army deposed president Mohammed Morsi in July.

Four Egyptian rights groups Monday denounced the military trials of civilians accused of attacking soldiers, saying the army had convicted more than 60 people since president Mohammed Morsi's ouster.

The NGOs urged interim president Adly Mansour, who was appointed by the army following Morsi's removal, to "immediately amend the law in order to prohibit trials of civilians by military tribunals".

An al-Qaida-inspired group based in Egypt's Sinai has said it was behind a bombing that targeted the interior minister in a failed assassination attempt, a statement on militant Islamist forums said.

"God has allowed your brothers in Ansar Beit al-Maqdis to shatter the security organization of the murderer Mohammed Ibrahim through a martyrdom operation," the group said in the online statement, pledging further attacks.

Witnesses said Egyptian military helicopters launched a second day of air raids on Sunday in Sinai in what the army described as "the largest military operation" to uproot Islamist militants.

Apache helicopters hit targets in north Sinai near the Rafah border crossing with the Islamist Hamas-ruled Gaza Strip, witnesses said.

Egypt's state prosecutor said Sunday that Muslim Brotherhood supreme guide Mohammed Badie would stand trial in a second case over clashes in which several demonstrators were killed, judicial sources said.

Fourteen people, including several top figures in the Brotherhood, the group from which ousted president Mohammed Morsi hails, will stand trial along with Badie at a date that has yet to be decided, the sources added.

Former presidential candidate and opposition leader Amr Moussa was on Sunday elected head of Egypt's 50-member panel that has been tasked with drawing up a new constitution.

The panel was named a week ago by interim president Adly Mansour to draw up a revised constitution in the wake of the ouster by the army of former president Mohammed Morsi on July 3.

Egyptian and Syrian drug traffickers set fire to their ship carrying more than 30 tons of hashish before being arrested by Italian police in the central Mediterranean, police said Saturday.

Italian drug busters had been tipped off "three days ago that a major drug shipment was being transported on the cargo ship en route in the Mediterranean", Italian police said in a statement.

The Italian coast guard said Saturday it had rescued more than 700 migrants and refugees, including many Syrians and Egyptians, from four struggling boats, the latest in a surge of refugee arrivals.

Coast guard and navy vessels rescued the migrants from troubled boats off the coast of Sicily on Friday and Saturday, rushing four of them -- a mother, father and their two young children -- to hospital for emergency care, the coast guard said.

Egyptian military helicopters conducted several air strikes in the Sinai peninsula on Saturday as armored vehicles surrounded suspected militant hideouts, army officials said.

The airstrikes took place south of the town of Sheikh Zuwayid and near the border with the Gaza Strip, the officials said.