By Shaimaa Fayed and Yasmine Saleh
CAIRO (Reuters) - Egypt branded Islamist gunmen who killed 16 police near the Israeli border as "infidel" and promised on Monday to launch a crackdown following the massacre that strained Cairo's ties with both Israel and Palestinians.
An Egyptian official has said "Jihadist elements" crossed from the Gaza Strip into Egypt before leading the assault on a border station. They then stole two armored vehicles and tried to smash their way into Israel, but were killed by Israeli fire.
Israeli Defense Minister Ehud Barak said on Monday that eight assailants died in the attack, adding that he hoped the incident would serve as a "wake-up call" to Egypt, which he has long accused of losing its grip in the desert Sinai peninsula.
The bloodshed represented an early diplomatic test for Egyptian President Mohamed Mursi, an Islamist who took office at the end of June after staunch U.S. ally Hosni Mubarak was overthrown last year in a popular uprising.
Mubarak cooperated closely with Israel on security and suppressed Islamist movements such as Mursi's Muslim Brotherhood whose leaders often voiced hostility towards the Jewish state.
Egypt's military, which still holds many levers of power in the most populous Arab nation, called the attackers "infidels" and said it had been patient until now in the face of the instability in Sinai.
"But there is a red line and passing it is not acceptable. Egyptians will not wait for long to see a reaction to this event," it said in a statement on its Facebook page.
A demilitarized Sinai is the keystone of the historic 1979 peace deal between the two countries.
But for the past year there has been growing lawlessness in the vast desert expanse, as Bedouin bandits, jihadists and Palestinian militants from next-door Gaza fill the vacuum, tearing at already frayed relations between Egypt and Israel.
Addressing a parliamentary committee in Jerusalem, Barak praised the work of Israeli forces in blunting Sunday's attack, with the Israeli airforce swiftly swinging into action and destroying one of the vehicles as it tried to breach the border.
"Perhaps it will also be a proper wake-up call to the Egyptians to take matters in hand on their side in a firmer way," he said.
SEALING THE BORDER
Mursi has promised to honor Egypt's 1979 peace treaty with Israel and has done little to suggest a major shift in ties. Army generals who served under Mubarak and ruled Egypt until last month still have broad influence over national security.
The new president has also reached out to Hamas, the Islamist rulers of the Gaza Strip that borders Egypt and Israel, and Sunday's killings could jeopardize those closer ties.
Egypt closed its border crossing into Gaza overnight, cutting off the sole exit route for most Palestinians at the height of the Muslim-fast month of Ramadan.
Hamas condemned the killings of the Egyptians and immediately sealed the warren of smuggling tunnels that connect Gaza with Egypt after Cairo said the gunmen had used these links to reach their territory.
Many key goods, including oil, pass through the tunnels, and a prolonged closure could stymie life in the coastal enclave.
Egyptian media speculation focused on Hamas as being involved in the attack, but experts urged caution.
"We should not do what we always do and rush to conclusions," said Safwat al Zayaat, a military analyst. "No one has provided any proof."
Hamas, while hostile to Israel, is considered too moderate by many Salafi Islamists and has at times clashed with them in security sweeps. It has said it is investigating the incident and had no information indicating the gunmen came from Gaza.
Last August, eight Israelis died in a cross-border Sinai attack blamed on Palestinian militants from Gaza. In June, an Israeli worker died in another incident on the desert frontier.
A Jihadist group called the "Magles Shoura al-Mujahddin" took responsibility for the June incident, saying it did so "without considering any claimed or imagined borders between Muslim countries. The Mujahddin has no word in their dictionary called borders except the boundaries of God."
No one claimed immediate responsibility for Sunday's attack.
Israel urged it citizens last week to leave the Sinai, citing the threat of a possible assault. On Sunday morning, an Israeli air strike killed a Palestinian gunman from a radical Islamist group and wounded another as they rode a motorbike in southern Gaza near the Egyptian border.
Hours later, the group of unidentified gunmen ambushed the Egyptian border police - who had gathered to break the Ramadan fast after sunset - and opened fire, killing 16 security forces personnel and wounding at least seven.
They then commandeered two vehicles, but one of them exploded before it could breach the frontier and the second was hit by the Israeli air force at the Kerem Shalom crossing, a zone where the Israeli, Egyptian and Gaza borders intersect.
Israeli media said the military had been on a high state of alert and had reacted rapidly to the attempted incursion.
"A very great disaster was prevented here," said the chief of the Israeli armed forces, Lieutenant-General Benny Gantz, adding that it was "a very complicated attack by terrorists linked between the Sinai and Gaza".
(Additional reporting by Yusri Mohamed in Sinai, Allyn Fisher-Ilan and Nidal al-Mughrabi in Gaza and Tamim Elyan and Ahmed Tolba in Cairo; Writing by Tom Pfeiffer; editing by Crispian Balmer and David Stamp)
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