Men swinging sticks and soldiers firing rifles attacked protesters demanding Yemen's president be brought to trial over the killings of anti-government demonstrators, wounding 10 people, witnesses and a medic said.
The protesters were heading toward the city's edge Friday to greet a march of thousands arriving from the city of Taiz, about 170 miles (270 kilometers) to the south. The four-day march, dubbed the March of Life was due to reach Sanaa on Saturday.
The lengthy march, a first in the 10 months of demonstrations, aims to pressure a new national unity government and parliament to reject a deal granting President Ali Abdullah Saleh immunity from prosecution in return for stepping down after more than 33 years in power. New presidential elections are set for Feb. 21.
The deal has failed to end the protests, which began in February and immediately drew a harsh government crackdown. The unrest has further destabilized a fragile and impoverished nation best by numerous conflicts and home to a dangerous al-Qaida offshoot.
The parliament is expected to discuss the immunity issue Saturday.
Protester Abdel-Hadi al-Azazi said the Friday's crowds making their way to the edge of Sanaa were attacked by stick-wielding men in plain clothes. Then, troops loyal to Saleh fired at them.
The medic, speaking on condition of anonymity because he is not authorized to brief journalists, said 10 people were injured, including one in serious condition with a gunshot wound to the head.
"Our rally rejects the immunity to Saleh and his regime members and we are calling for him to be put on trial for the killing of protesters," said Munther al-Asbahi.
The U.N. Security Council said Thursday it expects presidential elections in Yemen to go ahead as scheduled on Feb. 21 and rival parties to honor the deal that led Saleh to hand power to his vice president.
The council said in a statement Thursday that the national unity government installed on Dec. 10 and the parties must implement the deal "in a transparent and timely manner, and in a spirit of inclusion and reconciliation."
The council said it also expects other parts of the agreement to be honored, including the writing of a new constitution, initiation of a national dialogue, and a program of reforms to tackle "the profound security, humanitarian and economic challenges that Yemen faces."
(This version CORRECTS the distance between Taiz and Sanaa).)