Cameroon's government says it has launched air strikes against Nigerian Islamic extremists to dislodge about 1,000 fighters who seized a military base.

A statement Monday says two bombing raids and a heavy firefight put the insurgents to flight from Achigachia base.

It says the insurgents attacked five villages along several fronts on Cameroon's northern border with Nigeria over three days before they over-ran the military base Sunday.

The government said President Paul Biya ordered the air strikes to respond to "a change of strategy on the part of the assailants." It gave no death toll.

Neighboring countries increasingly are being drawn into Nigeria's 5-year Islamic uprising, which has killed thousands and driven refugees across borders into Cameroon, Niger and Chad. Nigerian extremists have been recruiting fighters in all three countries.