|Ali Abdullah Saleh's return to Yemen has infuriated many who thought they had seen the last of him [EPA]
Opposition tribesmen have shot down a fighter jet outside the capital Sanaa and captured its pilot as tens of thousands of Yemenis continue to protest against President Ali Abdullah Saleh's return from Saudi Arabia.
A military official said the aircraft, a Russian-made Sukhoi fighter, had been shot down on Wednesday while conducting a routine mission.
A tribal source told the Reuters news agency that fighters shot down the plane using anti-aircraft weapons and detained the pilot when he jumped from the wreckage in the mountainous area of Naham.
The tribesmen are believed to be allied to leading dissident General Ali Mohsen al-Ahmar and are battling Saleh's elite Republican Guard for control of the area.
Some tribes have aligned with protesters seeking to oust Saleh, who unexpectedly returned to Yemen
last week from Saudi Arabia during a wave of violence in the capital that left more than 100 people dead.
Saleh's return has infuriated many Yemenis who thought they had seen the last of him when an attempt on his life in June forced him to fly to neighbouring Saudi Arabia for medical treatment, but he defied the odds on Friday by landing in Sanaa.
Ally turned foe
Saleh is now opposed by former allies such as Mohsen and the influential al-Ahmar family that heads his own Hashed tribal federation.
Before his return, protesters trying to expand their camp in Sanaa were caught up in a battle between Saleh's forces and soldiers loyal to Mohsen.
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At least 100 people, mainly protesters, were killed.
While violence has dipped since Saleh came back, tensions are still high and many fear the lull will eventually give way to an even bloodier confrontation, if not all-out civil war.
Organisers were trying on Tuesday to build up the numbers of demonstrators by planning less risky routes through the capital after the violence that had kept some off the streets.
Saudi Arabia and the US supported Saleh in the past to contain an active al-Qaeda wing that has taken root in Yemen, but growing lawlessness is fanning fears of a civil war that could shake one of the world's top oil-producing regions.
Gulf nations seeking to broker a power transition have expressed concern over Saleh's repeated failure to sign agreed deals.