Demonstrators have again taken to the streets, condemning the brutal crackdown by forces loyal to the president in several cities.

Meanwhile the opposition on Thursday accused embattled President Ali Abdullah Saleh's regime of "massacring" the peaceful protesters in a bid to derail a Gulf-led transition plan.

On Wednesday, security forces backed by snipers on rooftops fired into about 100,000 people in Sanaa, killing 12 and wounding some 190. Opposition parties called the shootings a "massacre" and a crime against humanity.

Shooters took aim at immunity deal?

The protesters who were fired upon had taken to the streets to rally against a power-transition initiative that was set up the previous weekend between members of the opposition coalition - the Joint Meeting Parties (JMP) - and Saleh.

The JMP had offered Saleh immunity in exchange for his resignation 30 days hence, and a deal was looking close.

But protesters throughout the country were incensed, feeling that their grassroots movement was being overstepped by the JMP, and marched against the initiative on Wednesday.

For its part, the JMP said the shootings were a conscious bid to derail the power-transition deal.

Clinging to power

Saleh has managed to cling to office since the uprising began in Yemen in early February, inspired by revolts elsewhere in the Arab world. There have been protests nearly every day.

And bloody events are far from unknown in this uprising. Since calls for Saleh's resignation began, at least 130 demonstrators have been killed.

Still, some experts say it is unlikely that the president will hold on to power for long.

Complicated opposition movement

"The number of people in the protest movement has grown steadily," said Gregory Johnson, a Yemen expert at Princeton University. "It includes separatists from the south, rebels from the north, tribes from other regions, students - even members of the ruling party and people in the army."

Saleh, who took office in 1978, has Yemen's deeply embedded patronage system to thank for the fact that he is still in power, Johnson said. And he has managed to play his rivals against one another as long as he's been in power.

"He managed to see to it that they focused on each other, not on him," Johnson said. But now, Johnson said, Saleh's worst fears are coming true. "His enemies are building a temporary and practical alliance. He won't manage to survive politically."

When Saleh took over the country, "no one thought he would stay longer than eight months," said Elham Manea, a Yemeni political scientist at the University of Zurich, who was born in Egypt. But he became a "master of political survival" by using the patronage, nepotism and cronyism to his advantage, she said.

Story of a failing state

After North and South Yemen were unified in 1990, Saleh took charge of the entire country. But falling oil production slashed Yemen's income. Its financial situation was precarious, then miserable. Yemen went into a free-fall of joblessness and poverty. It is highly unstable, with the government having to contend with rebels, separatists and Islamic extremists, and a society facing complex problems of tribal structures and religious mores.

Many political scientists consider it a failing, if not failed, state.

It is this situation that has young Yemenis from the urban centers - Sada, Sanaa, and Taiz - up in arms, Manea said. And it's a situation made worse by the fact that there are an estimated 50 milllion arms in Yemen.

Observers says Saleh appears to be sitting on a tinderbox - but they note that a regime change is unlikely to make Yemen more stable, either.

Princeton's Johnson says it is unlikely that the disparate group of protesters can build a functioning replacement government. "Whatever sort of government will follow Saleh is still wide open," he said.

Author: Dominik Peters/Jennifer Abramsohn AP/dpa
Editor: Rob Mudge