The chief executive of Israel's national airline has reportedly threatened to stop offering flights to Cairo.
Eliezer Shkedi, who runs El Al, wrote in a letter to Foreign Minister Avigdor Lieberman that he was considering pulling the route between Israel and its southern neighbour.
The flights have been in operation for more than 30 years, as part of the agreement signed in the 1979 peace accord. But Mr Shkedi, whose letter was published in Maariv newspaper, said it was no longer viable.
The service has been operating only on a sporadic basis since the Arab Spring. "Operating the flight route to Cairo and maintaining the necessary infrastructure for that requires a large amount of security and
operational resources, and heavy economic expenditure," he said in the letter, which Mr Lieberman's office confirmed having received and said it was investigating.
"Without any commercial justification and in light of the high economic cost of operating this line, El Al cannot continue to bear these heavy expenses, and therefore is intending to stop operating the route to
Relations between Israel and its southern neighbour have been tense since the overthrow of the Mubarak regime last year, amid rising concern that the Muslim Brotherhood-controlled government will seek to end the
peace treaty. Cancelling the flights will be interpreted as a breakdown in the relationship between the two countries, although Yigal Palmor, from Israel's Foreign Ministry, told AP that if the service was not run
by El Al, another Israeli airline would have to take over.