Four Spanish aircraft have joined the efforts of more than 250 Portuguese firefighters battling a large forest fire in an isolated mountainous area in northern Portugal, AFP reported.

The fire, which broke out in the Viana do Castelo region, is spreading in two different directions and is difficult to control due to strong winds. One firefighter was injured.

Due to high temperatures and winds, authorities have declared the highest level of fire alert in much of northern and southern Portugal.

The fires are an annual disaster in the country during the summer season, but experts say they are becoming more frequent and intense worldwide due to rising global temperatures. | BGNES