ISTANBUL — Turkey’s prime minister sharply criticized the U.N. Security Council on Saturday for its failure to agree on decisive steps to end Syria’s civil war, as NATO ally Germany backed the Turkish interception of a Damascus-bound passenger jet earlier in the week.

Recep Tayyip Erdogan told an international conference in Istanbul that the world was witnessing a humanitarian tragedy in Syria.

“If we wait for one or two of the permanent members … then the future of Syria will be in danger,” Erdogan said, according to an official interpreter.

Russia and China, two of the five permanent Security Council members, have vetoed resolutions that sought to put concerted pressure on Damascus to end the conflict and agree to a political transition.

Erdogan called for a reform of the Security Council, which he called an “unequal, unfair system” that didn’t represent the will of most countries.

He spoke as Foreign Minister Ahmet Davutoglu met with Arab and European leaders amid growing tensions between TurDavutoglu met Saturday with Arab League chief Nabil Elaraby, German Foreign Minister Guido Westerwelle and U.N. envoy on Syria Lakhdar Brahimi.

He told reporters after the meetings that Turkey was prepared to use force again if it was attacked, just as it did last week when a shell fired across the border from Syria killed five Turkish villagers.

“If a similar incident occurs again from the Syrian side, we will again take counter action,” he told reporters, stressing that the border between Syria and Turkey is also the frontier of NATO.

One week after the shelling, Turkey intercepted a Syrian passenger plane en route from Moscow to Damascus and seized what it said was military equipment on board.