Fire engines rushed to downtown Berlin on Wednesday after a major blaze broke out at a construction site of the royal palace.

The fire started outside the Stadtschloss in two tar kettles, causing a propane gas cylinder to explode. One person has been injured and about 80 emergency personnel were on the scene.

The police said there was no indication yet of foul play and that investigations would start once the fire has been extinguished.

The junior minister for culture, Monika Gruetters, said: "Pictures of fire above the entrance to the palace sent shivers down all our spines."

The Humboldt Forum, a museum due to open in the palace around autumn, said work on the building would not be slowed by the fire. A cultural center is also in the offing.

Construction work at the palace started in 2013 and costs have spiralled since then. A major chunk of the expenses is being sourced from federal state funds.

The 15th century Stadtschloss was used by Prussia's Hohenzollern dynasty as a winter residence until the end of World War I, when Germany's last emperor, Wilhelm II, was forced to give up the throne.

The baroque palace was demolished by the East German government in 1950 after being damaged in World War II bombing.

Reconstruction has been controversial, as it meant tearing down the "Palace of the Republic" that stood on the same spot until 2008.

Housing the East German parliament and a leisure center until the country's reunification in 1990, the building was dear to many citizens of the former communist state.