A Yemeni security chief survived an assassination attempt on Saturday in the south of the country, where three people were killed in clashes between his forces and separatists.
The Defence Ministry said Abdulwahab al-Wali, head of the central security forces, escaped the attack by unknown gunmen in the town of Mukalla, but two of his bodyguards were wounded.
Southern Yemen, which was an independent state until 1990, is troubled by both separatist unrest and an insurgency led by Islamist militants linked to al Qaeda, a source of concern to Gulf states and the West.
Wali survived a previous assassination attempt last year, one of a string of attacks on military, political and militia leaders and officials. Many have been blamed on the Islamists, but the authorities did not say whether any group was suspected of Saturday's shooting.
In other developments, medical and security sources said three people were killed and 14 wounded in clashes between Yemeni security forces and separatists in the south.
Separatist leaders had called for a day of civil disobedience in major southern towns and cities after the deaths of six people in protests on Thursday.
The resurgent movement for a south Yemen state has aggravated political instability in the Arabian Peninsula country, where Washington fears political chaos is giving al Qaeda space to operate.
Shops, bakeries and schools were closed in many southern cities and transport was paralysed after roads were blocked with stones and burning tyres, witnesses said. Many government employees did not turn up for work.
In Aden, capital of the former South Yemen, one person was killed and nine were wounded in clashes on Saturday, medical sources said. Witnesses said armoured vehicles patrolled the streets.
One person was killed in Mukalla and another in Ghayl ba Wazir district in eastern Yemen, while five were wounded, the sources said. The Islah party, one of the most powerful in Yemen, said separatists had set fire to its headquarters in Mukalla.
North and south Yemen were unified in 1990 after the Communist-led southern government collapsed. Northern forces won a brief civil war four years later after the south tried to secede from the union.
The secessionist movement gained strength during mass, nationwide street protests against former president Ali Abdullah Saleh in 2011, which forced the veteran strongman from office a year ago.
Southern Yemenis complain of discrimination by the government in the north. Yemen, which borders the world's top oil exporter, Saudi Arabia, is also facing a northern rebellion by Shi'ite Muslims.