Forces operating out of the Egyptian-controlled Sinai Peninsula fired two medium-range Grad missiles at targets in southern Israel on Saturday.
The missiles landed near the Negev town of Mitzpe Ramon and the Uvda Airfield, where Israel is mulling the construction of a new international airport. Both sites had never before been targeted by terrorist rocket fire.
There were no injuries or damage reported.
The attacks coincided with the final round of voting in Egypt's first presidential election since the ouster of former dictator Hosni Mubarak.
Many Israeli officials believe the attacks were ordered by the Muslim Brotherhood, whose candidate, Mohammed Mursi, appeared poised to win the Egyptian presidency as the polls drew to a close on Sunday.
One official told Ha'aretz that Sinai Bedouins who were supplied by Hamas had carried out the attack, at the behest of the Muslim Brotherhood.
Israel fears that if the Brotherhood completes its takeover of Egypt (the party won a majority in parliament a few months ago), it will allow the Sinai to become an even more dangerous base of terrorist operations in order to draw Israel into direct conflict.
A senior defense official told The Jerusalem Post, "This is a sensitive time for Egypt and we are prepared for the possibility that there will be a further escalation from the Sinai."