Rescuers recovered the bodies of an officer and two soldiers, and were looking for a fourth body in the rubble. Another soldier was injured in the collapse, said the official, who spoke on condition of anonymity because he was not authorized to brief journalists.
Egypt's military has been sealing hundreds of smuggling tunnels under the Gaza border because authorities believe they are used to smuggle weapons into the restive Sinai Peninsula, where Islamic militants routinely carry out attacks on soldiers and police.
The interior ministry said Saturday that security forces have arrested 52 suspected militants who operated in eight different cells with the aim of targeting Egypt's infrastructure, including power stations, railroads, water plants and other services.
Ministry spokesman Hani Abdel-Latif said the suspects were apprehended in Giza -- a district of the capital -- Alexandria, two Nile Delta provinces and two southern provinces. He said the suspects attacked and vandalized a train as well as power and mobile pylon poles. He said they are also accused of obstructing traffic on main roads and plotting attacks against police.
Abdel-Latif said some of the suspects were plotting to disrupt the academic year by spreading chaos among students in Alexandria, Egypt's second largest city, and attacking university staff in the Nile Delta city of Zagazig.
He said some of the suspects were linked to the Muslim Brotherhood, which the government has declared a terrorist organization following the July 2013 ouster of Islamist President Mohammed Morsi, who hails from the group.
Protests on university campuses have become the main form of rallying for Morsi supporters. Security forces have cracked down hard on such protests.
The Brotherhood has denied involvement in any violent attacks. Most of the main attacks since Morsi's ouster have been claimed by smaller, more radical groups.
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