ADEN Feb 21 (Reuters) - At least four people were killed and 40 wounded in south Yemen on Thursday when security forces opened fire to disperse a protest by secessionist activists in the port city of Aden, medical sources and witnesses said.
Witnesses said the security forces shot at dozens of separatists as they staged a demonstration against President Abd-Rabbu Mansour Hadi on the anniversary of his election.
A local security official said one person had died, without elaborating. Witnesses and medical sources gave a different account, saying four people were killed, all men.
Spokesmen for the security services and the government were not immediately available to comment.
North and South Yemen unified in 1990 when the collapse of the Soviet Union undermined the communist south's economy. But political harmony was short-lived and an attempted southern secession in 1994 prompted a brief civil war, won by the north.
Hadi was appointed in February 2012 after popular protests forced his predecessor Ali Abdullah Saleh to step down under a deal brokered by Yemen's rich Gulf neighbours.
The protests left the Arab world's poorest country in a state of turmoil, emboldening one of al Qaeda's most active wings, Yemen-based al Qaeda in the Arabian Peninsula (AQAP), and reviving separatist sentiment in the south.
Southern Yemenis have complained of discrimination and secessionists want to build a socialist state separate from the north.
The separatists had gathered on Thursday to protest against the holding of celebrations by Hadi's supporters in the southern port city, the former capital of independent South Yemen, intended to mark the completion of his first year in power.
A witness said the military brought in armoured vehicles to Aden's Khor al-Maksar and Crater neighbourhoods where most of the protests were taking place.
Tackling lawlessness in Yemen, which lies near important oil shipment routes and flanks the world's biggest oil exporter Saudi Arabia, has become an international priority.
Washington and other Western governments regard AQAP as one of the most dangerous offshoots of the militant network. The group has planned attacks on international targets including airliners and pledges to topple Saudi Arabia's ruling family.
(Reporting by Mohammed Mukhashaf; Writing by Mahmoud Habboush; Editing by William Maclean and Pravin Char)