ADEN, Yemen: The death toll from clashes between security forces and separatists in southern Yemen rose to four on Friday after two protesters died of their wounds, according to medical and security officials.

More than 50 people were wounded as Yemenis marked the first anniversary of the election of President Abed Rabbo Mansour Hadi on Thursday. The election - in a one-candidate referendum vote - was part of a U.S.-backed transfer of power deal following a year-long uprising that ousted longtime autocratic ruler Ali Abdullah Saleh.

The clashes erupted in the southern city of Aden as pro-Hadi demonstrators gathered to celebrate the anniversary. Officials say separatist fighters tried to storm the gathering, prompting security forces to open fire.

Yemen's north and south were united in 1990.

Separately, Yemen's south has also been plagued by lawlessness and a fractured military. Al-Qaida took advantage of a power vacuum there to take over towns and villages in 2011 during the uprising against Saleh.

Security forces retook control last year, but al-Qaida remains active, launching attacks and assassinations on security forces and intelligence officials that have killed dozens.

Yemeni security officials said Friday that two suspected al-Qaida militants were shot dead in clashes with security forces in Aden.

The officials said soldiers and policemen also raided a suspected al-Qaida hideout at dawn in the city of el-Mansoura. They said militants inside fired rocket-propelled grenades at security forces in a firefight that lasted nearly an hour. Two of the men were arrested and another two fled the scene.

All officials spoke on condition of anonymity because they were not authorized to speak to the media.