At least three people are known to have died in a suicide car bombing that targeted Republican Guard troops camp in Bayda, 170km from Sanaa, the Yemeni capital.
Two bombers drove a car packed with explosives into the army base on Saturday, killing themselves and a soldier, the defence ministry said.
Witnesses said the blast devastated the three-storey building.
The explosion was apparently followed by an exchange of fire between armed men and the Republican Guard troops, who are led by Ahmed Saleh, son of the former president, Ali Abdullah Saleh, who formally stepped down less than a week ago.
"The explosion was very loud and took place in Dar al-Nasr, which is a military site of the Republican Guard," said a website close to Ali Mohsen al-Ahmar, a general who defected from Saleh's side in the early days of an uprising against him last year.
"Residents of the town were frightened by the force of the blast, which was felt more than two kilometres away and damaged dozens of neighbouring houses and blew their windows out."
Bayda borders Abyan province, an al-Qaeda stronghold in Yemen's south.
Al-Qaeda in the Arabian Peninsula (AQAP) claimed responsibility on Wednesday for a suicide attack on a presidential palace in Hadramawt province, in the southeast, that killed 26 Republican Guard soldiers last week.
That attack came as Abd-Rabbu Mansour Hadi, the first new president in Sanaa since 1978, took the oath of office as Saleh's successor.
AQAP said that the bombing of the palace in Hadramawt's provincial capital, Mukalla, was "a clear message to the US ambassador" after alleged remarks he made "about restructuring the Yemeni army".
"This is a message to say that the US project in Yemen will not succeed and that our operations will target this project and its tools wherever they may be," AQAP said.
In an address to the nation straight after being sworn in to succeed Saleh, Hadi vowed to press the fight against al-Qaeda and restore security across the Arabian Peninsula country.
"It is a patriotic and religious duty to continue the battle against al-Qaeda," Hadi said.
"If we don't restore security, the only outcome will be chaos."