German Foreign Minister Johann Wadephul on Monday promised Romania and Bulgaria support against Russia as he set off for a two-day visit to the EU countries.

The two states are "partners that are crucial for Europe's security and stability," Wadephul said ahead of his departure.

"South-eastern Europe is a strategic centrepiece of our continent," he argued.

The threat to the EU's external borders and on NATO's south-eastern flank war can be seen on the Black Sea amid Russia's war in Ukraine, the minister said.

"This is also where it will be decided whether Europe remains capable of acting - in terms of security, solidarity and the further development of our union," he added.

Given that the Black Sea is a border region to the war in Ukraine, Wadephul's Bulgarian counterpart Georg Georgiev emphasized when they met on Monday evening: "Our concern is that the Black Sea is increasingly present on the agenda of NATO and the European Union."

Bulgaria, he said, has a great interest in maintaining the region's stability.

Ahead of their meeting, Wadephul said that Bulgaria serves as a model for the countries of the Western Balkans, showing how closely security and integration belong together.

He described the country's imminent accession to the eurozone as a strong signal of stability for Sofia and for Europe as a whole.

Bulgaria is due to replace the lev with the euro in January, becoming the 21st member of the eurozone.

After Wadephul's meeting with Georgiev, he was expected to fly on to Bucharest for talks with Romanian Foreign Minister Oana Țoiu on Tuesday.

With regard to recent violations of Romanian airspace by Russian drones, Wadephul said that attacks on the sovereignty of a NATO partner were unacceptable.

"We are clearly determined to protect and defend Europe together with Romania," he said.

The Foreign Office in Berlin said Wadephul's talks would cover economic cooperation, efforts to boost European competitiveness and the EU's enlargement agenda.

Wadephul had originally planned to start his trip in Athens for talks with his Greek counterpart Giorgos Gerapetritis, before continuing to Sofia. However, the Athens leg was cancelled after Gerapetritis travelled to Egypt for the signing ceremony of the Gaza peace plan.

German foreign minister lauds Bulgaria, Romania as 'crucial' partners