For the fourth day in a row unarmed protesters have been shot dead in Yemen's capital Sana'a after government loyalists opened fire on another mass demonstration calling for president Ali Abdullah Saleh's resignation.
Tuesday's attack, which resulted in the death of seven people and more than 50 wounded, brings the death toll of this week's government crackdown to 35, further dimming the prospect of a diplomatic solution to Yemen's ongoing political turmoil.
In an effort to pile further pressure on their autocratic ruler, who recently returned from Saudi Arabia after receiving treatment for burns sustained in a June assassination attempt, protesters have been escalating their campaign by marching out of their protected sit-in area and into government strongholds.
On Tuesday morning the narrow streets of downtown Sana'a were packed with tens of thousands of men and women kicking up dust with their feet and shouting "Oh Saleh, the courts are waiting with you." A shirtless young man shimmied down a lamppost after scrawling "Leave you murderer" across a billboard of the president's face.
The rally was scattered when plainclothed gunmen hiding in the trees of the al-Qa'a garden opened fire on the protesters with kalashnikov rifles, witnesses said. Government troops arrived in armoured trucks firing teargas and jets of water at the remaining crowds. In the ensuring mayhem activists were seized by the Republican Guard, the elite unit led by Saleh's son Ahmed.
"We have the names of five women who were taken hostage by the security forces today," said Abdulrahman Berman, a lawyer from the Sana'a-based human rights group, Hood. "We also have first-hand accounts of injured protesters having their phones and wallets stolen and being dragged away by the gunmen."
The latest bout of violence coincides with a renewed effort by the United Nations to try to ease the country's embattled ruler from power. The security council is expected to make a decision this week on a resolution that would call for Saleh to "immediately sign and implement" a plan drawn up by the Gulf monarchies which requires him to cede power in exchange for immunity from prosecution.
But a spokesmen for the UN's human rights office said on Tuesday that any power-transfer deal including blanket immunity for the president would be illegal. "International law is pretty clear that amnesty cannot be granted to someone who could face war crimes charges," said UN spokesmen Rupert Colville.
As the UN deliberates, Yemen's nine-month uprising is heading towards potentially more violent conflict. The pro-democracy demonstrators are backed by a division of heavily-armed defected soldiers under the command of renegade army general Ali Mohsin al-Ahmar who defected to the opposition in March. On Monday Sana'a was rocked by deafening explosions and machine gun fire as the al-Ahmar's troops and the Republican Guard hurled mortars and anti-aircraft missiles at each other's bases in a battle for the capital.