* Seven others also arrested in Jaar
* Plot/violence show militants still a serious threat
SANAA, Aug 8 (Reuters) - Yemen has foiled a plot by an al Qaeda-linked cell to carry out attacks inside the capital Sanaa and seized 40 belts packed with explosives, the mayor said on Wednesday, highlighting the risks posed by Islamist militancy in the impoverished Arab state.
The Defence Ministry said seven militants had also been detained in the southern town of Jaar, where a suicide bomber killed 45 tribal fighters earlier this week and threatened further attacks on a bigger scale.
Yemen declared victory in June over militants calling themselves Ansar al-Sharia (Partisans of Islamic Law), but they continue to pose a serious threat in a country that borders top oil producer Saudi Arabia, despite losing control over territory they controlled for most of last year.
A local official said the target of the suicide bombing earlier this week - Abdul Latef Sayed, the head of a tribal fighting force - had narrowly escaped death again on Wednesday.
Militants had parked a car loaded with explosives outside his house in Jaar, the official said.
Sayed has now been targeted in two assassination attempts in just four days. The militants say it is revenge for siding with the army during a U.S.-backed military campaign against Islamist fighters in Abyan province. He was wounded in the first attack.
"Whatever happens, we will work to cleanse the city of Jaar of these terrorist elements, whatever the cost," Sayed told Reuters via telephone soon after Wednesday's blast, in which nobody was injured.
Tribal fighters drove away the militants behind the attack, killing one and wounding another, the same local official said.
Ansar al-Sharia went on the offensive last year when former leader Ali Abdullah Saleh was distracted and grappling with protests that eventually toppled him, seizing several towns and declaring them Islamic emirates.
The seven men arrested in Jaar included a Somali national and a militant leader known as Abu Musaab who was responsible for al Qaeda's finances in Abyan, the Defence Ministry said on its website.
Ansar al-Sharia is linked to al Qaeda in the Arabian Peninsula, which U.S. officials have described as the most dangerous offshoot of the global militant network.