Loyalists of Yemen President Ali Abdullah Saleh on Friday attacked demonstrators gathered south of the capital calling for the leader's trial, a protest organiser told AFP.
Further south, in Abyan province, seven soldiers were killed late Thursday near Zinjibar in an ambush by Al-Qaeda suspects, a military source said, adding three militants were also killed in subsequent fighting.
Assailants, some of whom were armed, attacked a group of 2,000 demonstrators in Hizyaz, a suburb south of Sanaa, before they could join a rally headed to the capital, said Mondher al-Asbahi.
"Dozens of demonstrators were wounded, struck by stones, and one was hit by a bullet," said Asbahi, a member of a Taez youth group organising the rally.
The "March for Life" procession, which kicked off in the southwestern city of Taez, has amassed tens of thousands of participants along the 270-kilometre (167 mile) road to Sanaa.
The demonstration is likely to reach the capital on Saturday, Asbahi said.
Tribesmen are escorting them to ensure the security of the march, which was the target of an armed attack in the province of Dhamar, a tribal chief told AFP.
He added that Saleh's partisans began to gather 30 kilometres south of Sanaa in bid to "block the march."
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A security services source told AFP that their were plans for military reinforcements as the march enters Sanaa to "guarantee the safety of its participants and prevent the entry of any armed participant."
Those marching hope to pressure the new unity government to put Saleh and his chronies on trial over his government's crackdown on opposition demonstrations, which has left hundreds dead since January.
Several demonstrations have called for Saleh to be tried for murder, nepotism and corruption, since he signed a Gulf-brokered deal which calls on him to step down in February in exchange for immunity.
Elsewhere, 10 people were killed in a sixth night of clashes pitting militants linked to Al-Qaeda against Yemeni troops trying to retake Zinjibar, Abyan's provincial capital.
"A military vehicle was ambushed by members of Al-Qaeda east of Zinjibar and seven soldiers died," a military source said.
"Three extremists were killed" in a subsequent gunfight," the source added.
Meanwhile, the Yemeni air force carried out four raids in the southern city of Jaar, also in Abyan province, he said, without being able to specify the number of casualties.
Residents, however, said four "Qaeda" militants were killed in the raid.
Government forces have been backed by tribal fighters and sometimes supported by US drone strikes in their battle against the Partisans of Sharia, an insurgent group that took over most of Zinjibar in May.
Al-Qaeda has profited from the instability caused by 11 months of protests against Saleh, strengthening its positions across the south of the country.