At least two armed men from the separatist Southern Movement were killed and 20 others, including five soldiers, were injured on Friday in clashes with the army troops in Yemen's southern port city of Aden, witnesses and medics told Xinhua.
The army troops fired into the air to disperse a demonstration organized by the separatist Southern Movement, which was followed by armed clashes between the two sides, a witness said.
The clashes lasted for more than two hours, leaving at least two separatists killed and 15 others wounded, added the witness.
Meanwhile, a doctor at Basuhib military hospital said that at least five injured soldiers were receiving treatment there.
Hundreds of separatist gunmen gathered in al-Mansoura city on Friday to stage the weekly protest of "the Southern Detainee's Day " to demand the release of activists in prison, according to a member of the separatist Southern Movement.
South and north Yemen unified peacefully in 1990, but the relationship had deteriorated by 1994, when a southern insurgency was quelled in a civil war. Calls for separation were renewed in 2007.