Egypt's military ruler warned on Sunday of "extremely grave" consequences if the turbulent nation does not pull through its current crisis.

Field Marshal Hussein Tantawi, in comments carried by the nation's official news agency, also urged voters to turn out for the parliamentary elections starting on Monday.

Syrian forces killed at least 15 civilians on Sunday, six of them in the flashpoint region of Homs that has been under siege for several weeks in an operation to crush dissent, a rights group said.

The latest violence came as the Arab League voted to impose a raft of diplomatic and economic sanctions against President Bashar al-Assad's regime for defying an ultimatum to allow observers into the country.

Kuwait's public prosecutor on Sunday extended the detention of 24 opposition activists for three weeks pending trial for storming parliament while freeing seven others on bail, their lawyer said.

Thousands of supporters meanwhile camped outside the palace of justice for the fourth night in a row in solidarity with the detainees ahead of an opposition mass rally on Monday to press for the government's resignation.

Bahrain and Qatar on Sunday called on their citizens to leave unrest-swept Syria after the United Arab Emirates also advised its citizens to stay away.

The call, issued on the day the Arab League was deciding on sanctions against Damascus over its deadly crackdown on dissent, was issued because of instability in Syria, said Bahrain's foreign ministry.

Israeli warplanes watched two strikes on the Gaza Strip overnight in response to rocket fire from the Hamas-controlled Palestinian territory, an army spokesman said in a statement Sunday.

"In response to rocket fire towards Israel this weekend, the airforce targeted sites of terrorist activity in the south and the center of the Gaza strip during the night," said the spokesman.

Morocco's moderate Islamist party won a parliamentary election for the first time, preliminary results showed Saturday, the latest religious party to achieve huge gains on the back of the Arab Spring.

The victory by the Justice and Development Party (PJD) comes just one month after Islamists won Tunisia's post-revolution election and days before their predicted surge in Egyptian polls.

Leading Egyptian political figure Mohammed el-Baradei said on Saturday he was prepared to forgo a presidential bid if asked by the country's military rulers to be interim prime minister, his office said.

El-Baradei, who met earlier with the head of the ruling Supreme Council of the Armed Forces, said he was "ready to renounce the idea of being a candidate in the presidential election if officially asked to form a cabinet."

Arab finance ministers gathered in Cairo on Saturday drew up a list of economic sanctions against Syria that they will present to foreign ministers for adoption, a communique said.

The recommendation -- which includes a ban on Syrian officials visiting any Arab country and the freezing of government assets -- comes after President Bashar Assad's regime defied an ultimatum to allow in observers amid a lethal crackdown on protest.

Israel warned on Saturday that it would cut the supply of water and electricity to the Gaza Strip if rival Palestinian movements Fatah and Hamas form a unity government.

"The foreign ministry is examining the possibility of Israel pulling out of the Gaza Strip in terms of infrastructure," Deputy Foreign Minister Danny Ayalon told the daily Yediot Aharonot website.

Syrian Foreign Minister Walid Muallem accused the Arab League on Saturday of "internationalizing" the deadly crisis hitting the country since pro-democracy protests began more than eight months ago.

The accusation came in a letter addressed to the Arab League as ministers from the group gathered in Cairo to draw up sanctions against Syria to punish President Bashar Assad's regime for defying an ultimatum to allow in observers and pressing a deadly crackdown.