BEIRUT (AP) _ Energized by the killing of Libya's Moammar Gadhafi, thousands of protesters in Syria and Yemen poured into the streets and said their longtime rulers will be next.

Syrian President Bashar Assad's security forces opened fire on the protesters, killing at least 24 people nationwide on Friday, according to activists. It did not stop the crowds from chanting, “Your turn is coming, Bashar.”

Yemenis delivered a similar message to President Ali Abdullah Saleh, who survived an assassination attempt in June. ``Gadhafi is gone, and you're next, oh butcher,'' they chanted.

The armed rebellion that drove Gadhafi from power _ with NATO air support _ appears to have breathed new life into the uprisings elsewhere in the Arab world.

``Our souls, our blood we sacrifice for you, Libya!'' Syrian protesters chanted Friday.

Gadhafi was killed Thursday under still-murky circumstances, although he apparently was dragged from hiding in a drainage pipe, begging for his life.

His brutal end less than two months after he lost control of his oil-rich nation follows the ouster of Tunisia's Zine El Abidine Ben Ali, who has been driven into exile, and of Hosni Mubarak of Egypt, who is in jail and facing charges of complicity in the deaths of more than 800 protesters.

All three uprisings have given Syrian protesters hope. One banner read, ``Ben Ali fled, Mubarak is in jail, Gadhafi is killed, Assad ... ?''

The uprisings in Syria and Yemen have proved remarkably resilient even as the governments relentlessly try to crush the revolts. The U.N. estimates the Syrian crackdown has killed some 3,000 people since March; in Yemen, the figure is believed to be around 500 since late January.

Yemen is falling deeper into turmoil, and Islamic militants have taken advantage of the chaos to seize control of several cities and towns in a southern province. That has raised American fears that the militants may establish a firmer foothold in the Arabian Peninsula country, which is close to vast oil fields and overlooks key shipping routes.

Syria's mass demonstrations, meanwhile, have shaken one of the most authoritarian regimes in the Middle East, but the opposition has made no major gains in recent months, holds no territory and has no clear leadership. The regime has sealed off the country and prevented independent media coverage, making it difficult to verify events on the ground.

``Gadhafi's death will boost the morale of Syrians,'' Syria-based activist Mustafa Osso told the AP in a telephone interview. ``It will make them continue until they bring down the regime.''

The Local Coordination Committees, a Syrian activist network, put Friday's death toll at 24 nationwide. It said 19 of those killed died in the flashpoint city of Homs, where military operations in pursuit of activists and anti-government protesters are a daily occurrence. The LCC said three others were killed in Hama and its suburbs, one in the northern Idlib province and one in the Damascus suburb of Saqba.

The Syrian Observatory for Human Rights, an activist group based in Britain, said at least 15 people were killed in Hama. It also reported heavy fighting in Saqba between troops and gunmen thought to be army defectors.

In the Syrian town of Qusair near the Lebanese border, Syrian forces closed all mosques to prevent people from gathering. The weekly protests usually begin as Syrians pour out of mosques following Friday afternoon prayers.

In Washington, State Department spokesman Mark Toner decried the ``appalling'' violence by the Syrian government.

``Let's be completely clear that the onus for these deaths lies on the Syrian government, on Assad, on his regime, who continue to kill innocent civilians,'' he told reporters.

Toner said the U.S. supported Arab League efforts to mediate dialogue. But, he said, ``we're not particularly optimistic since the Syrian government has shown no interest in pursuing any kind of dialogue.''

The unrest in Syria could send unsettling ripples through the region, as Damascus' web of alliances extends to Lebanon's powerful Hezbollah movement and Iran's Shiite theocracy.

In many ways, the Syrian uprising has taken cues from the Libyans recently.

Syria's opposition formed a national council like the Libyans' National Transitional Council, hoping to forge a united front against Assad that Syrians and the international community could rally behind.

And with the successes of armed Libyan revolutionaries present in their minds, many Syrian protesters say they are starting to see the limits of a peaceful movement. Some want to take up arms and are inviting foreign military action, hoisting signs that say ``Where is NATO?'' and urging the world to come to Syria's aid.

Syrian opposition leaders, however, have not called for an armed uprising and have for the most part opposed foreign intervention. In addition, Washington and its allies have shown little appetite for intervening in another Arab nation in turmoil.

There is concern that Assad's ouster would spread chaos around the region, and that his opposition is too fragmented. Various parties are vying for power as they seek an end to more than 40 years of iron rule by Assad and his late father, Hafez.

The Syrian protesters have been largely peaceful, though there have been some clashes in border regions between Syrian forces and apparent defectors from the military.

The growing signs of armed resistance may give the government a pretext to use even greater firepower against its opponents. Authorities have already used tanks, snipers and gangster-like hired gunmen known as ``shabiha.''