In retaliation, the group appears to have changed tactics from trying to hold territory to carrying out deadly attacks.
Two weeks ago, a top intelligence official, Col. Abdullah al-Ashwal, was killed in a drive-by shooting in Sanaa by his own informant, who appeared to be working for al-Qaida.
Over the summer, a suicide bomber killed Maj. Gen. Salem al-Quton, the top commander of the southern region who led the war against al-Qaida. Col. Abdullah al-Maouzaei, charged with hunting down members of al-Qaida, was killed when his vehicle blew up as he turned on the ignition outside his home in the southern port city of Aden. A top intelligence official in Sanaa and Omar Barsheed — who headed the Military Academy and was nominated to head presidential guards — both died in similar bombings. The press secretary of the president escaped an assassination attempt.
One of the worst attacks took place on May 21 when a suicide bomber — who turned out to be a son of a colonel— blew himself up in the middle of military rehearsal killing nearly 100 of them. A month later, al-Qaida suicide bomber detonated his explosives among a crowd of Yemeni police cadets, killing at least 10.
"These operations aim at paralyzing the military forces and breaking their morale," said Mansour Hayel, a political analyst.
Officials said that detained al-Qaida members confessed that the slain officials were on a hit list that includes many of Hadi's men, particularly those he depends on in his war against al-Qaida.
Hadi has reached out to tribal leaders in the south, trying to secure their help against al-Qaida, after many of its militants who fled this year's offensive took refuge in tribal-controlled areas in the mountains in the southern and eastern parts of the country. During the offensive, the Yemeni military has often relied on local tribal militias for help.
On Tuesday, while meeting with tribal leaders from Shabwa province — a one-time stronghold of al-Qaida — Hadi pressed for unity with the government, warning that the government "will not tolerate anyone who helps al-Qaida."
But al-Qaida is sending signals to the tribes as well. Authorities on Tuesday discovered three decapitated bodies dumped in an open-air market in the eastern province of Marib.
Local media reported that CDs found next to the bodies showed the men confessing to being government informants against al-Qaida and admitting they had put tracking devices on cars that became targets for U.S. drone strikes. One of the men said he worked for a tire repair shop and used to plant chips in militants' vehicles while replacing their tires.