CAIRO // Sixteen Egyptian soldiers killed when a Sinai border post was attacked in a flurry of automatic gunfire and grenades poses a daunting security challenge to the president, Mohammed Morsi, just more than a month into his term.
The attack on Sunday, when the soldiers were breaking their Ramadan fast, injured seven others, three of them critically.
The attackers stole an armoured personnel carrier and a lorry laden with explosives that blew up near the border, but it was unclear whether it was hit by the Israelis or destroyed by the attackers by accident. The armoured personnel vehicle was destroyed by the Israeli air force after entering Israeli territory near the Karm Abu Salem border crossing. Eight of the attackers were killed, but none had been publicly identified as of yesterday.
Mr Morsi said on Sunday night that "there's no room to appease this treachery, this aggression and this criminality" and said that the country's military and security forces would extend "full control" over the area. "Sinai is safe," he said.
Mr Morsi also declared three days of mourning for the soldiers killed in the attack.
Security and military officials said at least two helicopter gunships arrived in the border town of El Arish yesterday to join the hunt for the rest of those responsible.
In Israel, officials struck a more alarmist tone. Ehud Barak, the defence minister, called the attack a "wake-up call" for the new Egyptian president to take stark measures to regain control over Sinai.
"I think that the risk of a very large terrorist attack was averted," Mr Barak told the Israeli parliament's foreign affairs and defence committee yesterday
"This was a very important operational success in the battle that is raging there and maybe a proper wake-up call for the Egyptians to take matters into their own hands on their side in a stronger manner."
Security analysts yesterday said that the motive of the attackers may have been a bid to spark confrontations to unravel the 1979 peace treaty between Egypt and Israel.
"It fits into a pattern of radical Jihadis trying to provoke some sort of escalation in violence between Egypt and Israel that would completely scuttle what remains of the peace treaty and plunge back both countries into a profound state of enmity," said Bruce Hoffman, the director of the Centre for Security Studies at Georgetown University in the Washington. "It also could be an attempt to embarrass the Egyptian military and undermine its continued influence in the country and its governance."
The security situation in Sinai has been a simmering problem for decades but, after the uprising last year that toppled the regime of Hosni Mubarak, attacks have become more numerous and ambitious.
There have been 15 bombings of a gas pipeline that took natural gas to Israel and Jordan since the uprising, causing long interruptions in the flow.
Last August, unidentified assailants attacked an Israeli bus driving on Route 12 in Israel near the border of Egypt, killing seven Israelis and one soldier. Also in August, 2011, Israelis inadvertently killed five Egyptian security officers while chasing alleged militants near the town of Eilat into Egypt. That precipitated protests against Israel in Egypt outside of the Israeli embassy and marked a new low in relations between the two countries.
In South Sinai, several American tourists have been kidnapped for short periods during the past year by Bedouins who are aggrieved by the poor infrastructure in the region, dismal economic development and claims of stolen lands.
The twin problems of Bedouin discontent and the use of Sinai by Islamic extremist groups bent on waging jihad against Israel through Egypt has led to one of the country's greatest security problems in decades.
Yesterday, in the first direct indication that the attackers may have had the help of Palestinian militants, the statement from the Egyptian army said "elements from the Gaza Strip" aided the attackers by shelling the border crossing as Sunday's attack was taking place.
If true, the incident could have wider political ramifications, said Geoffrey Aronson, the director of research at the Foundation for Middle East Peace in Washington.
Egypt has sought to be an arbitrator in the reconciliation negotiations between Hamas in Gaza and Fatah in the West Bank. Any proof that the militants came from Gaza could undermine Egypt's relations with Hamas.
"At the very least, the attack underscores the real dangers of interstate conflict that has now appeared in a way that you cannot deny in Sinai," Mr Aronson said. "For many months, everyone has tried to keep the lid on this issue through informal consultations and, in many respects, just hoping for the best. But this was a military operation that penetrated Israel and that is a wake-up call to people who were hoping they could easily contain this."
The problem is an unwelcomeditraction for Mr Morsi, a long-time member of the Muslim Brotherhood, who is seeking to prove to Egyptians that he can make a positive effect on their daily lives through improving government services and restoring the economy.
It is also a problem he may not have the powers to combat. The military curtailed many of Mr Morsi's powers over national security in a constitutional addendum it issued before he took office.
The question will be whether Egyptian authorities can find a solution to the Bedouins grievances, while stamping out extremism through military operations.
"This will pressure Morsi to take a closer look at the Sinai and realise that the problem is not simply Bedouin oppression," said a source familiar with security issues in the Sinai who declined to be named because of the sensitivity of his involvement in the region. "There are criminal elements out there as well as extremists, whose interests do not coincide with Egypt's interests."