Witnesses said the blast happened as Major General Mohamed Nasir Ahmed’s motorcade left the prime minister’s office in Sanaa after a cabinet meeting.
Interior Minister Abdul Qader Qahtan told state television that seven security guards and five civilians were killed and 12 other people were wounded.
Aides said the minister was unhurt and had told Prime Minister Mohamed Basindwa he was safe.
“A booby-trapped car waited for the motorcade of the minister near the government offices and as soon as it moved, it exploded,” a security source said. “A security car was totally destroyed and all its occupants were killed, but the minister survived because his car is armoured.”
Officials say yesterday’s attack was the fourth assassination attempt against the defence minister since a new government was formed last December, after a power transfer deal under which long-ruling president Ali Abdullah Saleh stepped down.
No one immediately claimed responsibility for the attack, which followed the government’s announcement of the killing of Said al-Shehri, deputy head of the Yemen-based branch of Al Qaeda.
Al Qaeda blames the defence minister for leading a campaign that drove it from strongholds in southern Yemen, an area that Washington considers one of the main battlefields in its global campaign against Islamist militants.
Yemen’s government said it had killed Shehri in a military operation, but Yemeni security sources said he was one of six suspected militants killed last Wednesday in a strike by a US drone.
The US does not comment on its use of unmanned aircraft against militants, which has enraged the public in Yemen because of civilian deaths. A separate apparent drone strike last week hit the wrong target and killed 10 civilians.
“Shehri’s death is a painful blow to Al Qaeda after the grievous losses it suffered in Abyan,” state-owned daily Al Thawra said in a front page headline, referring to a province where the army had forced Islamist militants from this year.
Shehri was wanted by Yemeni, Saudi and US authorities over his role in Al Qaeda in the Arabian Peninsula (AQAP).
A former inmate of the US prison camp at Guantanamo Bay, Shehri was freed to Saudi Arabia by the George W Bush administration in 2007. After a time in a Saudi militant rehabilitation programme he escaped to Yemen and is suspected of a role in a 2008 attack on the US embassy.
Last year Yemen claimed it had killed him, only for it to emerge Shehri was still at large.
Analyst Nasser Arrabyee said the Yemeni government wanted to claim a success to win the public over to the US-led campaign.
“People are angry because of the mistakes that were made when people were killed,” he said. “But most people know that Al Qaeda should be defeated and is dangerous for the country.”
Leaked US diplomatic cables showed Saleh agreed in 2009 to a covert US war on Islamist militants and would claim Yemeni responsibility for attacks when necessary.
Saleh was eventually swept from power under a negotiated deal after a popular uprising that became one of the most drawn out and violent of the “Arab Spring” revolts, during which Al Qaeda seized towns and villages in the south.
Thousands of Yemenis marched through Sanaa yesterday to demand Saleh be tried over corruption and the deaths of protesters, denouncing the US- and Saudi-backed power transfer deal that gave him immunity from prosecution for standing down.
“The people want the fall of his immunity,” they chanted, in a play on the Arab uprising slogan “the people want the fall of the regime”. Security forces closed off streets around Saleh’s house to prevent the marchers getting near.
