Germany's Foreign Minister Sigmar Gabriel on Tuesday warned against a unilateral American recognition of Jerusalem as the Israeli capital. Speaking at a conference in Berlin, Gabriel added a fierce statement to his warning, saying that Germany would have to "spell out where the limits" of its solidarity stood.

Germany was the latest country to join the wave of diplomatic warnings emanating mostly from Arab countries and cautioning U.S. President Donald Trump against declaring Jerusalem to be Israel's capital. Also on Tuesday, Trump spoke with Palestinian President Mahmoud Abbas, Prime Minister Benjamin Netanyahu and Jordan's King Abdullah about Jerusalem. During the call with Abbas, Trump told the Palestinian president he intends to move the U.S. Embassy from Tel Aviv to Jerusalem, Abbas' spokesman said.

The German foreign minister addressed the crowd at the Berlin Foreign Policy Forum held by the Körber-Stiftung Foundation, which is one of the most important conferences in the foreign policy field that takes place annually in the German capital and hosts diplomats, politicians and government and military officials.

"There are signs that America is going to recognize Jerusalem as the capital of Israel, without having reached an agreement with Europe on this subject we all know what the repercussions to that may be," he said in a speech.

"The German stance on this question remains unchanged: The solution to the Jerusalem question can only be found through direct contacts between the two sides. Anything that could exacerbate the crisis is counterproductive," Gabriel clarified in a sharply-worded statement.

Gabriel went on to add that "in any case Germany can't afford to wait for decisions from Washington or just [wait until they are made] and then comment on them. We need first and foremost to describe our positions and in some cases - sometimes vis a vis our allies - spell out where the limits of our solidarity are."

Germany's top diplomat also said that facing this dilemma on the backdrop of recent developments in the Middle East "is not easy for us, it's a new thing."

According to German sources, the retesting of Germany's limits will take place primarily versus the U.S., which appears to be acting on the highly-disputed subject without consulting with its traditional, European allies, a move that European leaders are concerned by.

"The European Union can only survive if it defines its own interests and puts its power on display," the German foreign minister said.

In his speech at the forum, Gabriel lamented the American "withdrawal from the role of a reliable guarantor of Western multilateralism" under the auspices of President Trump.

This is not the first time the German foreign minister expresses his dismay with the policy of Prime Minister Benjamin Netanyahu's government. In the past, Gabriel refused to receive a phone call from the Israeli premier after the latter cancelled a meeting with him because he insisted on meeting with representatives of left-wing Israeli NGOs such as "Breaking the Silence."

The Israeli NGO seeks to provide testimonies by veteran IDF soldiers who describe their experiences of serving in volatile areas such as East Jerusalem, the Gaza Strip and the West Bank. Netanyahu fiercely opposes the group, and has spoken against its actions on several occasions.