Sharp rise in arrivals seen even though many find they are no better off in impoverished nation than they were at home.
At least five fighters with suspected links to al-Qaeda have been killed in an apparent US drone strike in a remote part of southern Yemen, officials said.
The fighters, who were reportedly heavily armed with weapons and explosives, were killed in an air strike on their vehicles in Shabwa province on Thursday.
Two other fighters were wounded and another fled the scene after the strike, an official added.
“Five militants belonging to Ansar Al-Sharia were killed in a drone strike” in Shabwa, said a tribal chief.
Witnesses said the drone fired four missiles at the two cars as they travelled through the town of Saeed in Shabwa, a stronghold of the armed group.
“The two cars are still burning and we couldn’t get close to them because the drones are still hovering in the area,” said a local resident.
The tribal chief said gunmen suspected to have links with Al-Qaeda had earlier arrived in four vehicles and “set up a checkpoint on the road linking Saeed and Ataq,” Shabwa’s provincial capital.
The United States is the only country that has drones in the region and in recent months has been carrying out strikes on al-Qaeda targets in the south and east of the country.
During a visit to the United States last month, Yemeni President Abdrabuh Mansur Hadi acknowledged that drone strikes in his country took place with his approval.
“Every operation, before taking place, they take permission from the president,” Hadi told the Washington Post on September 29.
Hadi also spoke of a joint operations centre near Sanaa “that serves as an intelligence nerve centre for operations” against al-Qaeda in the Arabian Peninsula.
“You go to the operations centre and see operations taking place step by step,” Hadi said.
A security official told AFP that “two Al-Qaeda militants coming from Abyan province were arrested at Al-Alam checkpoint” east of the main southern city of Aden on Thursday.
Two others were arrested on Wednesday.