Protesterna i Egypten (2013)

In private, one senior Israeli official expressed alarm at U.S. President Barack Obama's condemnation of the bloodshed in Egypt and cancellation of a joint military exercise with Cairo.

"Eyebrows have been raised," the official said.

Israel worries that any sign of wavering U.S. support for Egypt's military may embolden Islamist militants sympathetic with the Muslim Brotherhood, ousted by the Egyptian army after a year in power.

Eiland backed the crackdown by Egyptian army chief General Abdel Fattah al-Sisi on the Brotherhood this week.

"Sisi in the situation he faced, had no choice but to do what he did," said Eiland, adding he thought Western outrage at the scale of the bloodshed was understandable. Almost 800 people have been killed so far.

Israel wants to avoid any disruption of its security cooperation with Egypt, which stems from a 1979 peace treaty - the first of only two such accords between Israel and Arab countries.

Military ties with Egypt have helped Israel strategically in a region where it is otherwise largely isolated, as well as rein in weapons smuggling to Palestinian militants in Gaza, which is ruled by Islamist group Hamas.

That cooperation has remained intact despite turmoil since Hosni Mubarak was toppled in 2011. Both sides are anxious to curb growing lawlessness in Sinai and Eiland said intelligence officials continued to work together to curb attacks from Sinai.

Israel says rocket strikes one towns across its southern border have increased from Sinai. An Israeli missile shield shot down a rocket fired at the resort of Eilat earlier this week.

Magles Shoura al-Mujahideen, a hardline Islamist group, said it carried out the attack in retaliation for the deaths of four militants in an airstrike in Sinai a week ago. Israel denies any role in that attack.

Eiland did not rule out "a one-off Israeli action" to take out a rocket launcher if Egypt were unable to prevent an attack in time, but thought Israel could rely on Egypt's military.