A German naval frigate sent to protect commercial ships in the Red Sea nearly shot down a US drone by mistake, German media reported Wednesday.

The German defence ministry confirmed a drone incident involving an allied nation occurred on Monday, without naming the country.

The "Hesse" frigate opened fire after efforts to identify an unknown drone "were unsuccessful", Defence Minister Boris Pistorius said during a visit to the German town of Oberviechtach, adding however that the target was "not hit".

The drone later turned out to be a "reconnaissance drone", he said.

According to Der Spiegel weekly, the frigate fired two missiles at the drone but both crashed into the sea because of "a technical defect".

Spiegel, without citing its sources, said the drone that was nearly downed was a US Reaper.

It might have been operating in the region "as part of an American anti-terror mission" unrelated to the Red Sea mission, Spiegel added.

The Frankfurter Allgemeine newspaper said it was "common knowledge that American combat drones are used in the region that have nothing to do with the operation in the Red Sea".

The German defence ministry said the frigate only launched an attack after none of its allies reported a drone in the area.

Spiegel said military officials believed the friendly fire incident showed that coordination between allies involved in various missions in the region around Yemen "needs to be improved".

The "Hesse" arrived in the region at the weekend as part of an EU mission to help secure international shipping in the Red Sea from attacks by Yemen's Iran-backed Huthis.

The German army earlier on Wednesday said the frigate had successfully thwarted an attack on Tuesday evening by shooting down two drones launched by the rebels.

The Huthis, who control much of war-torn Yemen, have been attacking the vital shipping lane since November in a campaign they say is in solidarity with Palestinians in Gaza amid the Israel-Hamas war.

The United States is spearheading its own naval coalition in the Red Sea and has conducted strikes on the Huthis in Yemen along with Britain.