Asked to specify the number of Al-Qaeda operatives in Yemen, he said: "I can't give you really an exact figure. Maybe hundreds of them, 200, 300. I don't have a real figure."
His comments come as Yemeni officials stepped up investigations into whether the Nigerian suspected in the attempted Christmas Day attack spent time with al-Qaeda fighters in the country in the months up to the attempted bombing.
Umar Farouk Abdulmutallab, 23, has reportedly told US investigators he was given training in Yemen where he also received the explosives used in the attempted bombing.
|Abdulmutallab reportedly told investigators he was trained by fighters in Yemen [AFP]
On Monday a group called al-Qaeda in the Arabian Peninsula, based in Yemen, claimed responsibility for the attempted bombing of a Delta Airlines plane as it approached Detroit.
In the wake of that incident, Al-Qirbi said it was important for countries to improve their intelligence sharing with Yemen, so it could be warned about the movement of suspects.
"We have to work in a very joint fashion in partnership to combat terrorism," he said. "If we do that, the problem will be under control."
He said the US, UK and the European Union could do a lot more to improve Yemen's response to fighters operating on its soil.
"There is support, but I must say it is inadequate," he said.
"We need more training, we have to expand our counter-terrorism units and this means providing them with the necessary training, military equipment, ways of transportation, we are very short of helicopters."