ADEN, Yemen: Three people were killed in clashes as southern separatists blocked roads in two Yemeni cities on Saturday, adding to the death toll of this week's violence in the troubled south of the country.

"A policeman was killed and another wounded in clashes when security forces intervened after gunmen from the Southern Movement blocked roads" in Aden, General Abdulhafez al-Saqqaf, head of its central security services, told AFP.

A soldier was also wounded, the official said.

Also in Aden, troops shot dead a southern activist, according to a medic at the city's Al-Naqib hospital and activists of the Southern Movement, which advocates the region's autonomy or independence.

Aden residents said dozens of separatists took to the streets of the Khor Maksar, Mualla, Sheikh Osman and Dar Saad districts, blocking roads, burning tyres and clashing with the army.

A security official told AFP that "supporters of the Southern Movement blocked roads and, when the army tried to intervene, gunmen among them deployed in buildings in these areas opened fire on troops, prompting the clashes."

The official, who asked not to be named, said the protesters were supporters of a hardline separatist faction led by exiled Ali Salem al-Baid, that has so far refused to take part in a national dialogue set to take place on March 18.

The activists were protesting "under the banner of civil disobedience," he said.

In the southeastern province of Hadramawt, where similar clashes took place on Saturday, police killed another protester, Southern Movement activist Nasser Bagzkoz told AFP.

"Police opened fire at a peaceful protest that took off in the town of Ghail Bawazir," 30 kilometres (18 miles) west of the provincial capital Mukala, killing protester Mohammed Buslama, he said.

Residents said gunfire rang across Mukala as separatists blocked roads and burned tyres.

The separatists also burnt down two offices belonging to the Islamist Al-Islah (Reform) Party, which backs President Abdrabuh Mansur Hadi, witnesses said.

A security official in Hadramawt said the local central security services head, Colonel Abdulwahab al-Wali, escaped an assassination bid by separatists who opened fire at him. His three guards were wounded in the attempt.

Lutfi Shatara of the Southern Movement told AFP that demonstrators in Aden were angry at Thursday's "massacre," referring to the police killing of five people in pro-independence protests.

South Yemen broke away in 1994, sparking a civil war, before it was overrun by northern troops. The Southern Movement has been divided over participating in Yemen's national dialogue.

All its wings had agreed to join the UN-backed talks except for Baid's faction which insists on full independence for the south, whose residents complain of discrimination by the Sanaa government.

The conference, originally set for mid-November, has been repeatedly delayed, mainly due to differences with the southerners.

During a speech in Aden to mark one year in power, Hadi on Thursday denounced "calls for armed conflict, which will lead to the loss of the southern cause," in an apparent reference to Baid's faction.