With Cairo lagging in the fight against Islamic State, Israel, which grew increasingly anxious because of the security situation in the nearby North African country sought to intervene, a report by New York Times revealed.
The report, citing current and former US and British officials, said Israeli forces had carried out more than 100 airstrikes in Egypt over the course of more than two years with Cairo's approval.
The report, which cited USA and British sources, claimed Israeli aircraft attacked targets in Egypt's Sinai Peninsula over 100 times in the past two years.
Egypt and Jordan are the only neighbouring countries having a peace agreement with Israel.
While there have always been suggestions of behind-the-scenes military and intelligence cooperation between Egypt and Israel, officials from both countries rarely comment publicly on them.
The NY Times alleged that attacks were aimed at Takfiri militant targets.
Egyptian President Abdul Fattah al-Sisi had declared on January 19 that thousands of members of the security forces have been injured in extremist attacks since 2014.
In order to cover their traces, when flying over Egyptian airspace, Israel only uses unmarked drones and ensures that its Israeli jets and helicopters cover up their markings.
The report said Sissi had kept the Israeli strikes secret, only letting a small group of military and intelligence officials in on the cooperation, and has kept northern Sinai a closed military area, barring reporters from the region.
The Associated Press, meanwhile, reported that the Egyptian Army was bulldozing homes and olive groves to build "a buffer zone" around North Sinai Province's only airport in the city of el-Arish. "Shared enemies like ISIS, Iran and political Islam have quietly brought the leaders of several Arab states into growing alignment with Israel - even as their officials and news media continue to vilify the Jewish state in public".
Saudi Arabia, United Arab Emirates and Bahrain have reportedly made significant overtures to Tel Aviv over the recent years.