A group affiliated with Islamic State has said it fired three rockets into Israel from Egypt's Sinai peninsula.
The affiliate, which calls itself Sinai Province, said it had acted in retaliation for what it says is Israeli support for the Egyptian army.
Israel said two rockets landed in the south of the country, causing no casualties or material damage.
At least 17 Egyptian soldiers and 100 IS militants have died in fighting in northern Sinai since Wednesday.
The clashes were triggered by a co-ordinated mass assault of IS militants on the town of Sheikh Zuweid.
Sinai Province claimed the rocket attack on social media on Friday.
The group said it had fired Grad rockets towards "occupied Palestine".
The Israeli military later said that two missiles landed in open areas in Israel's Negev region, causing no damage.
Sirens were heard in communities in Israel's Eshkol regional council, near the Gaza border.
"I trust the army and am certain that it will take all necessary measures to protect communities in the South," council leader Eshkol Gadi Yarkoni was quoted as saying the Haaretz newspaper.
Israel accuses Hamas, who run Gaza, of providing support for Sinai Province - a claim the Palestinian group denies.
Israel has a 240km (150 miles) border with the Sinai peninsula.
On Wednesday morning, militants launched near-simultaneous attacks against at least five military checkpoints and a police station in and around Sheikh Zuweid.
The attack was one of the largest co-ordinated assaults so far by the jihadists in Sinai.
Eyewitness reported seeing militants roaming the streets of the northern town, clashing with armed forces.
An Egyptian military spokesman, Brig-Gen Mohammed Samir, later told state TV that the situation was "100% under control".
Jihadists based in the restive region stepped up their attacks after the military overthrew Islamist President Mohammed Morsi in July 2013.
At least 600 police and armed forces personnel have since been killed.