Dahir said: "Two seriously injured soldiers were being removed from the truck. There was a lot of blood at the scene.
"Nobody knows whether the Ethiopian soldiers died or not."
Somalia's transitional government says Ethiopian soldiers are in the country to aid its operations against a campaign led by Muslim fighters, who were forced from Mogadishu in December after a short war.
A security source in Mogadishu said the Ethiopian truck was destroyed by an anti-tank mine set off by remote control.
The use of the remote device highlights the use of a new tactic by anti-government.
In a related development, local media said a Somali soldier was shot dead by unknown assailants late on Tuesday near Mogadishu's Bakara market.
The Muslim fighters have previously struck government buildings, convoys and Ugandan peacekeepers patrolling for the African Union (AU).
Ethiopia wants to pull its troops out of Somalia as soon as the AU force is up to strength, or has at least half its planned 8,000 troops deployed in.
Other African nations have resisted sending more soldiers to Somalia in the wake of attacks on AU peacekeepers.