The independent Yemen Post reported that southern separatists sparred with the Sunni rivals during demonstrations in the southern port of Aden.
Tensions are high as the country prepares to mark the anniversary of former President Ali Abdullah Saleh's resignation. He handed power over to his deputy, Abdu Rabbo Mansour Hadi, Feb. 27, 2012.
Saleh resisted pressure to stand down for much of 2011 as a wave of pro-democracy movements swept over much of the Middle East and North Africa.
The Yemeni report stated that one person was killed in Aden, though the circumstances of the incident were unclear.
Hadi announced plans for a national dialogue last month. Yemen has struggled with national security and southern separatist campaigns in the face of a threat from al-Qaida in the Arabian Peninsula.
A national dialogue conference is expected to culminate in preparations for a draft constitution. General elections should take place in 2014.
Yemen was united as a republic in 1990 though civil war dragged on for four more years.