A spokesman for the Supreme Council said thousands of protesters set fire to tyres and blocked streets [Reuters]

Thousands of separatists have marched through two cities in southern Yemen to demand that authorities release a leader of the southern secessionist movement.

The protests started on Wednesday following the arrest of Hassan Bamoum, the leader of the southerners' main faction, The Supreme Council for the Peaceful Southern Movement. The reason for his arrest was not clear.

Abdu al-Maatari, a spokesman for the southern movement, said around 5,000 protesters set fire to tyres and blocked streets in the city of Daleh before security forces cleared the crowds

On Thursday protesters attacked a military checkpoint and also tried to break into a jail, according to local officials.

The checkpoint clash occurred hours before about 4,000 people, according to local residents, took to the streets in the city of Daleh for a second day.

Hours after the protest, armed men threw a grenade at a military vehicle at a checkpoint, setting it ablaze and wounding four soldiers.

Two of the armed men, suspected to be separatists, were wounded in the attack, a security official said.

Other marches were held in Habilayn and Loder, two centres of protest in the south of the country, where marches are held every Thursday to advocate the release of prisoners.

Many Yemenis in the south, home to most of the country's impoverished oil facilities, complain of discrimination by a government that freely exploits the area's resources.

The Arabian Peninsula state is under international pressure to quell domestic conflicts like the southern separatist movement and bolster a shaky truce with Shia rebels in the north in order to focus on fighting a resurgent wing of al-Qaeda, which is said to be exploiting the country's instability.

North and south Yemen united in 1990 under Ali Abdullah Saleh, who is still the president. The bumpy merger led to a brief civil war in 1994 won by the north.

Yemen surged to the forefront of Western security concerns over the past year and last month the United Arab Emirates and Britain intercepted US-bound parcel bombs sent from Yemen and claimed by al-Qaeda's Yemen-based regional wing.

Source: Agencies