World powers weighed tough options to end brutality in Syria on Tuesday amid the aftermath of the now-infamous massacre in Houla.

Politicians and opposition forces have been going back and forth over the future of the Kofi Annan peace initiative, the need for more diplomatic arm-twisting and even the prospect of military intervention as the world community cries for an end to the Syrian conflict.

The incident occurred on Friday in the Homs province town of Houla, where more than 100 people died. The United Nations says government forces went house to house and slaughtered men, women, and children. The Syrian government is blaming the violence on "terrorists."

The violence has left more than 12,000 slain since March 2011, according to one count, and tens of thousands of people have been displaced.

What can the world do? Here are choices experts say the international community has:

Continue the U.N.-backed Kofi Annan plan:

U.N. and Arab League envoy Kofi Annan has proposed a six-point peace plan, ostensibly accepted by the Syrian government and opposition forces. It includes a cease-fire by all combatants, a call to pull back troops from major cities, and access for humanitarian groups. It also calls for a Syrian-led political process to resolve differences.

The cease-fire was forged April 12. A U.N. observation team is making sure the government is adhering to the plan and both sides are continuing the halt in violence.

But the future of this U.N. effort is in question because violence has continued despite the U.N. initiative. The Local Coordination Committees of Syria said on Saturday that more than 1,600 have been killed since Annan's initiative began.

Annan continued his diplomacy on Tuesday in a meeting with President Bashar al-Assad, urging adherence to the plan.

"We are at a tipping point," Annan said. "The Syrian people do not want the future to be one of bloodshed and division. Yet the killings continue and the abuses are still with us today. As I reminded the president, the international community will soon be reviewing the situation."

Andrew Tabler, Syria expert at the Washington Institute for Near East Policy said he thinks the denunciations over the massacre could prompt the regime to adhere to Annan's plan.

Elliott Abrams, senior fellow for Middle Eastern Studies at the Council on Foreign Relations, wrote on Tuesday the Annan plan "is in ruins."

"We will know in a few days whether Annan goes doggedly, indeed blindly, forward or salvages his own reputation by declaring his efforts at an end and demanding international action against Assad. Were he to do so, action might actually follow; it would be difficult for governments to turn away and dismiss his conclusions.

"So this week is a test for the former secretary-general. He may be remembered for this sorry turn in Syria -- or for demanding that governments face the truth and help the people of Syria put an end to the murderous Assad regime," Abrams said.

Jon Alterman, director of the Middle East Program at the Center for Strategic and International Studies, said "the utility" of the Annan plan is that it helped the world move forward on the issue. It won't necessarily change al-Assad's maneuverings, though.

"I think it's viable in determining greater international unity," Alterman said. "It may play a role in creating more international solidarity and a greater international determination to find some way out."

Provide military help:

While talk of military intervention is growing, a full-blown military operation like the one is Libya has not yet emerged.

Saudi Arabia, Qatar, and the Syrian Muslim Brotherhood have supplied rebels with "significant quantities of weapons" and Turkey has provided training and equipment, wrote James Traub, a fellow of the Center on International Cooperation and a columnist for Foreign Policy.com.

"Turkey will provide its territory for the training and organization of the Free Syrian Army, the United States will provide logistical and command-and-control assistance, and Gulf states will supply the hardware."

Traub wrote that the Obama administration "is said to be clandestinely helping direct arms to rebel forces" but "has admitted only to supplying communications equipment and other nonlethal assistance."

White House spokesman Jay Carney, said, "we do not believe that further militarization of the situation in Syria at this time is the right action."

The opposition has been fractious and decentralized, according to a number of experts. Traub said Annan, the United Nations, and others will help the opposition organize and grow, keeping the Syrian National Council "from collapsing into utter chaos, as it now threatens to do" and persuading the council, rebels, and the LCC "to work together."

Conservatives in the U.S. Congress and some voices in the Arab world have called for arming the opposition and criticized the Obama administration's stance as less than robust.