The Islamic State in Iraq and the Levant (ISIL) claimed responsibility for the car bomb attack, which injured 20 others.
ISIL said it targeted the area "out of revenge for the Muslims against the Houthi apostates."
Hours later, on Tuesday morning, Yemeni forces launched a Scud missile at a missile base in Saudi Arabia on Tuesday, Yemeni state news agency Saba quoted the military's spokesman as saying.
The car bomb “exploded behind the military hospital in Sanaa, which injured 28 people, including 12 women in a building where victims of a previous attack were being mourned," a medical source said.
Yehia Ali, a witness, told Reuters, "At approximately 11:30 we heard a loud explosion. It was a truly powerful explosion. We came out to see what happened, and the homes were severely damaged.”
"It was an explosive placed inside a car … that had been parked here since about 8 in the evening, and no one paid attention to it," Ali said.
A military alliance led by Saudi Arabia has been bombing positions of Yemen's dominant Houthi group and its allies in the army to dislodge them from the capital and restore the exiled president, Abd Rabbu Mansour Hadi.
Despite the months of airstrikes backing up the Houthis' armed opponents, the Houthis have not lost ground on the battlefield and have stepped up their exchanges of artillery and rocket fire with Saudi forces along the Yemen-Saudi border.
Al Jazeera with Reuters