A 3,400-year-old palace has been revealed on the banks of the Tigris river after drought caused water levels in a major reservoir to recede.

The Bronze Age site in Kurdistan, northern Iraq, dating to a period when the Mitanni empire held sway over a swathe of the Middle East, has been excavated for the first time.

Newly-discovered wall paintings inside the ancient palace have been hailed as an “archaeological sensation” and the wider site is one of the most important finds of recent decades, researchers said.

A joint German-Kurdish team worked on the excavation after a lack of rain and the need to release water from the reservoir at Mosul Dam to relieve drought conditions further south combined last autumn to reveal the palace.

The massive building, preserved up to a height of 7m and with walls 2m thick in places, would originally have been an imposing structure overlooking the Tigris valley atop an elevated terrace, archaeologists said. The Mitannis built a huge mud-brick wall to bolster its western front on the sloping terrain, it is thought.

In the 1980s, the area was flooded following the construction of the Mosul dam.

Ancient palace found near Tigris river Show all 7 1 /7 Ancient palace found near Tigris river Ancient palace found near Tigris river A room in Kemune palace during excavations University of Tubingen Ancient palace found near Tigris river A terrace wall on the western side of Kemune palace University of Tubingen Ancient palace found near Tigris river Excavations on the shore of the reservoir. Murals were found in this room University of Tubingen Ancient palace found near Tigris river A mural fragment University of Tubingen Ancient palace found near Tigris river Dr Ivana Puljiz University of Tubingen Ancient palace found near Tigris river A view of the southern portion of the palace University of Tubingen Ancient palace found near Tigris river A room of the palace during excavations University of Tubingen

The palace was in use for a long period, Dr Ivana Puljiz, of the University of Tubingen, said, with two phases of occupation clearly identifiable.

Excavations revealed a series of rooms of which eight have been partially explored so far, and clay tablets covered with ancient cuneiform writing found inside suggested it may have been part of the city of Zakhiku, archaeologists said. Another, larger city to the north may be linked, they believe.

Dr Puljiz added: ”We have also found remains of wall paintings in bright shades of red and blue.

“In the second millennium BCE, murals were probably a typical feature of palaces in the ancient Near East, but we rarely find them preserved.

“So discovering wall paintings in Kemune is an archaeological sensation.”

The palace was first partially revealed by low water in 2010, according to Dr Hasan Ahmed Qasim of the Duhok Directorate of Antiquities, but excavations were not possible at that time.

“The Mitanni empire is one of the least researched empires of the ancient Near East,” Dr Puljiz added.

“Information on palaces of the Mitanni period is so far only available from Tell Brak in Syria and from the cities of Nuzi and Alalakh, both located on the periphery of the empire.

“Even the capital of the Mitanni empire has not been identified beyond doubt.”