Lisbon: More than 100 bushfires have stretched thousands of firefighters to the limit in northern Portugal, the worst spate of fires in recent years that spread out of earlier in the week.

Portuguese Prime Minister Luis Montenegro has declared a state of calamity for the hardest-hit areas, invoking powers to mobilise more firefighters and civil servants. He also called on police investigators to redouble their efforts to find those who started the blazes and pledged help for those who have lost their homes or have been evacuated.

“We are well aware that these difficult hours are not over yet,” Montenegro told the nation in a televised address. “We have to continue to give everything we have and ask for help from our partners and friends so that we can reinforce the protection of our people and property.”

The European Copernicus satellite service said more than 15,000 hectares had been scorched and a combined 13 kilometres of fire fronts had been detected. It added that an area home to 210,000 people was exposed to the fire risk.

The hot, dry conditions behind the outbreaks in Portugal coincided this week with flooding in central Europe caused by storm Boris which killed at least 12 people. The European Union said the juxtaposed extreme weather phenomena were proof of a “climate breakdown”.

Spain’s military sent 240 soldiers and vehicles from its emergency response battalions specialised in combating fires to its neighbour.

Four water-dumping planes from France, two from Spain and two from Italy were deployed after answering an appeal to help their fellow EU member. Morocco likewise responded to a request by Portugal with two water-dumping planes.

“The thick smoke produced by most of these fires is making it very difficult for air units to operate,” said Civil Protection official André Fernandes. “We are still at high risk for forest fires over the next 48 hours.”