ISMAILIA, Egypt (Reuters) - An Egyptian court on Monday sentenced 14 Islamists to death for attacks on security forces in the Sinai Peninsula, showing Egypt's determination to put down militancy in a region critical to relations with neighbouring Israel.

ISMAILIA, Egypt (Reuters) - An Egyptian court on Monday sentenced 14 Islamists to death for attacks on security forces in the Sinai Peninsula, showing Egypt's determination to put down militancy in a region critical to relations with neighbouring Israel.

The Jewish state has voiced concern about security in Sinai, where at least four cross-border attacks have taken place since President Hosni Mubarak was toppled in February 2011.

The Islamist president, Mohamed Mursi, has made the issue a priority since he was elected in June.

Sixteen Egyptian border guards were killed in August, and hundreds of police and troops with tanks, armoured vehicles and helicopters have been sent to raid militant hideouts and seize weapons in an operation coordinated with Israel.

The court in Ismailia sentenced 14 members of the Tawheed wal Jihad ("Monotheism and Holy War") group to hang for killing three police officers, an army officer and a civilian in attacks on a police station and a bank in the town of Arish in June and July last year.

Eight were tried in absentia, court sources said. Four other militants were sentenced to life imprisonment.

"This court decision is a milestone. It gives a strong message to the militant groups that the state, President Mohamed Mursi's government, will not tolerate attacks on the Egyptian armed forces and police," said Nageh Ibrahim, an expert on Islamists who is himself a former militant.

The verdicts prompted cries from the accused.

"Mursi is an infidel and those who follow him are infidels," shouted one.

Others cried "God is Greatest" as they listened to the judge from inside their metal cage in court. The men all had beards and traditional white robes and some held Korans.

The prosecutor said that Tawheed wal Jihad ("Monotheism and Holy War") propagated a hardline Islamist view that allowed adherents to declare the head of state an infidel and to wage war on the government.

The same group was accused of carrying out a series of bomb attacks in 2004 and 2005 against tourist resorts in South Sinai, in which 34 people died.

Grand Mufti Ali Gomaa, Egypt's highest Islamic legal official, sanctioned the death penalty before it was pronounced.

"The accused wanted to spread corruption in the earth," he said. "They went out armed with deadly weapons, machine guns and explosives to target security forces ... all in the name of Islam. They therefore deserve the death sentence."

Ibrahim, who was jailed during the 1990s but later became one of the leading Islamists to call for an end to violence against the state, said the verdicts would deter other militants from attacking Israel.

"Mursi's government is adamant about stemming any attacks across the border because this will give Israel an incentive to reoccupy Sinai. Now is the time for development, not war," Ibrahim said.

The U.S.-brokered 1979 peace treaty between Egypt and Israel sets strict limits on military deployment in the Sinai, which is designated a demilitarised buffer zone.

(Additional reporting and writing by Marwa Awad; Editing by Kevin Liffey)