Yemeni forces shot dead one protester and wounded 16 others Friday as secessionists in the southern city of Aden defied a ban on protests, hours after another deadly clash.
Two years after the ouster of veteran strongman Ali Abdullah Saleh, secessionist leaders called for anniversary demonstrations to press their campaign for the restoration of the south's independence before union with the north in 1990.
Thousands of protesters marched on Aden's central government and diplomatic district of Khor Maksar after the main weekly Muslim prayers, an AFP correspondent reported.
But police fired live rounds and gas at the protesters as they neared the district's central Arood Square defying a ban on protests in the area.
One person was killed and 16 wounded, a medical source said. Activists said dozens more suffered from the effects of tear-gas inhalation.
"The south is a state and an identity," the protesters chanted.
Police also opened fire on a similar protest march on Khor Maksar late on Thursday, killing one demonstrator and wounding 12 others, medics said.
Video footage posted online showed police using tear gas to disperse dozens of protesters as they held evening prayers out in the open.
Authorities had announced a ban on all gatherings in the area, citing "extraordinary security conditions... and the need to pre-empt terrorist acts."
Aden's top security committee said only peaceful demonstrations with prior authorisation would be tolerated.
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But the protest organisers vowed to press ahead with their plans for a new march on Arood Square in defiance of the ban.
Faced with the deadly response by security forces, demonstrators set up two rallies nearby, the first some 500 metres (yards) from Arood Square, and the other in Muala Street.
"We swear by God! Sanaa will never rule over us," chanted thousands of protesters who brandished the flag of the formerly independent South Yemen.
A statement issued by protest organisers condemned the "brutal crackdown" and also reiterated their rejection of the national dialogue which agreed to divide Yemen into federal regions.
The agreement fell short of the aspirations of hardline southerners who had boycotted the talks, insisting on full independence.
Protest organisers urged the international community to support their "legitimate demand to regain independence with a fully sovereign state" in the south.
Saleh, who stepped down on February 21, 2012 after 11 months of deadly protests against his 33-year rule, led the crushing of a 1994 southern secession bid, which resulted in the occupation of the south by northern troops.
Security forces killed eight demonstrators in Aden on the first anniversary of his ouster and Friday's protests were also called to commemorate their deaths.
Saleh's successor, his long-time vice president Abdrabuh Mansur Hadi, had been due to step down at the end of a two-year transition.
But his term of office was extended in the face of persistent political unrest.