Israeli Prime Minister Benjamin Netanyahu on Sunday described the killing of three soldiers by an Egyptian border guard a terrorist attack and demanded a full joint investigation with Cairo.
In Cairo, Egyptian officials said senior intelligence operatives had travelled to Israel to work with their Israeli counterparts on the investigation, which is primarily aimed at clarifying the circumstances of the deadly exchange of fire on the border in the Sinai Peninsula.
An Egyptian policeman was killed in the exchange.
“Israel relayed a clear message to the Egyptian government. We expect that the joint investigation will be exhaustive and thorough,” Mr Netanyahu told his cabinet, in televised remarks about Saturday's incident.
“We will refresh procedures and methods of operations and also the measures to reduce to a minimum the smuggling and to ensure tragic terrorist attacks like this do not happen again.”
Egyptian officials said the intelligence operatives who travelled to Israel wanted to revise and upgrade with their Israeli counterparts the guidelines and preventive measures already in place on the border to ensure that Saturday's incident is not repeated.
The Egyptian officials requested anonymity because of the sensitivity of the subject.
Egypt and Israel have for years been closely co-operating on security and counterterrorism in the vast Sinai Peninsula, where Cairo has recently quietened an insurgency by militants in the area's north-east corner close to the border with Israel and the Gaza Strip.
The two countries also co-ordinate efforts to counter drugs and human trafficking. Additionally, Egypt is the main interlocutor between Israel and the militant Palestinian Hamas group that rules the Gaza Strip, frequently mediating in a bid to end hostilities between them.
The Israeli army said on Saturday that two soldiers – a man and a woman – were shot dead near the Egyptian border, and that a third was killed during an exchange of fire with an Egyptian policeman.
The Egyptian military said in a Saturday statement that “a member of the security forces breached the border's security barrier” while in pursuit of drug smugglers, leading to the death of three Israeli soldiers and injuries to two others.
The Egyptian security serviceman was killed in the exchange of fire, the statement said.
Israeli Chief of General Staff Maj Gen Herzi Halevi and the commander of the Southern Command conducted an investigation and assessment of the situation at the site of the incident, the Israeli army said on Saturday.
Hours before the deadly shooting, Israeli soldiers had foiled an attempted drug smuggling operation at the border, seizing contraband estimated to be worth 1.5 million shekels ($400,000), a spokesman said.
The spokesman added that no link had been established between the drug seizure and the attack along the border.
Egypt in 1979 became the first Arab state to sign a peace treaty with Israel. The border between the two former foes has been mostly peaceful since then, although drug smugglers have occasionally exchanged fire with Israeli troops.
There have been incidents in the past on the border, none of which posed a serious threat to the two neighbours' relations.
In 2011, assailants who came from Sinai killed eight Israelis in an ambush north of Israel's Red Sea port city of Eilat at the northern point of the Gulf of Aqaba. Pursuing Israeli forces killed seven of the attackers and five Egyptian policemen.
In 2012, three militants who infiltrated from Sinai were killed, as well as an Israeli soldier, in a clash along the border. In 2014, two Israeli soldiers on patrol were wounded by unidentified men who fired an anti-tank weapon from inside Sinai during a drug-smuggling attempt, according to the Israeli military.
And in 2015, rockets fired from Sinai hit southern Israel but caused no casualties. ISIS later claimed responsibility.