MADRID (AP) — Authorities in Spain say they have contained a major wildfire in the northeastern Catalonia region.

But they warn that wind and temperatures forecast to remain around 40 C (104 F) could give the blaze fresh impetus Saturday.

Miquel Buch, the regional interior minister, says the fire is close to being brought under control in the hilly area where it is still burning after four days. Almost 500 firefighters were at the scene.

He says 21 people involved in firefighting duties required medical assistance overnight.

Officials believe the fire broke out in a farm's fermenting pile of chicken dung and spread to the surrounding countryside.

Several other wildfires have broken out across Spain as hot air moving north from Africa causes a heat wave.