Yemen's military and Al-Qaeda suspects who fled an army offensive in the south clashed in a district near the capital Sunday, killing six troops and three jihadists, including a local leader, sources said.
And two overnight drone strikes targeted Al-Qaeda suspects in Wasl, a village in Arhab, 20 kilometres (12 miles) north of Sanaa, tribal sources in the area said.
The United States is the only country operating drones over Yemen, but US officials rarely acknowledge the covert programme.
Militants fled the drone strikes to a village in the same area, Ozer, where Yemeni troops launched a ground attack, according to the sources.
A security official said Yemeni anti-terrorism forces killed three Al-Qaeda militants and arrested four others.
The defence ministry said in a statement that top Al-Qaeda militant Saleh al-Tays, who is on a Yemeni list of most wanted jihadists, was killed in an operation in Sanaa province.
A security official told AFP Tays was among the three extremists killed in Arhab.
The ministry's news website 26sep.net, said Tays was involved in the January 21 killing in Sanaa of a Ahmad Sharafeddin, a key member of a Shiite Huthi rebel delegation to Yemen's reconciliation talks, as well as "foreign citizens and diplomats". It did not elaborate.
Tays had escaped two drone strikes, the last one in December.
In Sunday's operation the army also destroyed "four vehicles that were prepared to carry out suicide attacks" in the country, said 26sep.net.
The tribal sources told AFP that six members of Yemen's special forces also died in the Arhab fighting and that troops arrested 12 Al-Qaeda suspects -- eight Saudis and four Yemenis.
The army has sealed off Arhab, they said.
The sources added that in late 2011, the suspects had fought in Syria, where foreigners have joined the conflict between forces loyal to President Bashar al-Assad and rebels battling to oust him.
The militants returned to Yemen and were in Al-Qaeda's southern bastions of Shabwa and Abyan before an army offensive launched on April 29 drove them out to Arhab, they said.
The army says it inflicted heavy losses on Al-Qaeda in the offensive.
But analysts say the gains may have been the result of a tactical retreat by Al-Qaeda in coordination with powerful tribes.
Washington regards the jihadists' Yemen franchise -- Al-Qaeda in the Arabian Peninsula -- as its most dangerous and has stepped up drone attacks against AQAP leaders.
Late on Saturday, Yemeni warplanes raided the home of a suspected jihadist in Arhab who had also returned from Syria, the local sources said.
They reported casualties, without giving figures, and said the house was damaged and two cars were destroyed.
Al-Qaeda exploited the 2011 uprising in Yemen that led to the ouster of veteran autocratic president Ali Abdullah Saleh to seize large swathes of the south and east.
The army recaptured several major towns in 2012 but has struggled to reassert control in rural areas despite recruiting militia allies among local tribes.