Germany’s top diplomat pointed to a Berlin peace summit that took place in January, when international governments committed to upholding the long-flouted UN embargo.

Despite being hailed as a breakthrough at the time, the summit’s aims, focusing on reducing foreign involvement in the long-running civil war, have largely fallen flat.

“Ultimately, we have to be able to rely on everyone who signed the agreement in Berlin … adhering to what they signed,” Maas said.

“I also wouldn’t rule out further sanctions,” he added.

Maas’ trip to Abu Dhabi follows his visit to Libya on Monday, during which he discussed with Libyan Prime Minister Fayez Serraj ways to end the power struggle between the UN-backed leader and military strongman General Khalifa Haftar.

Serraj has the backing of Turkey and Qatar, while Haftar is supported by Egypt, Russia and the UAE.

The European Union has launched the Irini naval mission in a bid to enforce the arms embargo.

Meanwhile, Germany, France and Italy have moved to impose EU sanctions on individuals and companies that provide ships and aeroplanes for the transportation of arms.

So far there have been no punitive measures announced for the countries that send the weapons in the first place.

During his UAE visit, Maas also discussed the conflict between Israel and the Palestinians, reiterating his hope that the recent landmark deal to establish ties between Israel and the UAE will contribute towards peace in the region.

Under the deal, Israel has suspended its plans to annex West Bank territories, a precondition for the resumption of talks between the Israelis and the Palestinians, Maas said.

“It is actually easier for all sides to communicate directly with one another. And we will also try to do our part,” Maas said.

Ahead of his talks with UAE Foreign Minister Abdullah bin Zayed Al Nahyan, Maas called the Israel-UAE deal “historic.”

Palestinians, however, have reacted with anger at the fact that the UAE conditioned normalizing ties with Israel only on Israel suspending plans to annex parts of the occupied West Bank, and not on Israeli recognition of an independent Palestinian state with East Jerusalem as its capital.