Trump's victory in the US presidential election is met with praise from Europe, despite growing concerns about a possible economic crisis.

• For over a year, European diplomats and their leaders have been readying for the possibility of a Trump presidency.
• Several European leaders found Trump's confrontational leadership style during his first presidency to be unenjoyable, resulting in moments of tension.
• In 2020, many in Brussels rejoiced at Joe Biden's election victory, hoping for an improved relationship.

Despite a realization that renewed economic warfare could be imminent, European officials have congratulated Donald Trump on his victory over Kamala Harris.

European leaders and diplomats have been preparing for a Trump victory for over a year, with a growing emphasis on policies to safeguard the European economy from potential trade conflicts.

Several sources told CNBC that some European officials awoke on Wednesday with disbelief over the election results.

"One EU official, who wished to remain anonymous due to the delicate state of transatlantic relations, stated, "I am observing it, yet I am not as taken aback as before.""

The confrontational leadership style of former President Trump was not well-received by many European leaders during his first presidency, leading to several tense moments. Following his victory in 2020, there was widespread celebration in Brussels for the election of Joe Biden, who was hoped to bring about a more positive engagement.

Another unnamed source from the EU stated, "It is not good again."

The source acknowledged that while they were not as surprised as in 2016, they still echoed the feelings of the previous official.

EU leaders to meet Thursday

On Wednesday morning, Ursula von der Leyen, Emmanuel Macron, Pedro Sanchez, Giorgia Meloni, and Viktor Orban were among the first EU leaders to congratulate Trump.

Not all European countries share the same concerns about Trump. Hungary's Prime Minister Viktor Orban, who has expressed admiration for Trump in the past, has reportedly said that he would celebrate Trump's re-election by opening a bottle of champagne.

EU leaders will gather in Budapest for a regular meeting to discuss their plans for the transatlantic relationship.

The European Union will face consequences if it does not increase its purchases of American goods, as Trump has warned of imposing an additional 10% in tariffs on European nations.

The relationship between the EU and the U.S. is crucial for European nations, as they have the largest bilateral trade and investment partnership globally. In 2021, this partnership reached an all-time high of 1.2 trillion euros ($1.29 trillion), according to data from the European Commission.

Additional tariffs could exacerbate the already sluggish economic growth in the EU.

The European Political Community (EPC) will have a first discussion on the outcome of the U.S. election starting on Nov. 7, according to a third anonymous EU source who spoke to CNBC Wednesday morning.

The third diplomat stated that the main challenge will be Ukraine if Trump's rhetoric does not differ significantly. The diplomat's main focus is to maintain European unity.

'Worst economic nightmare'

On Wednesday morning, ING analysts stated that the reelection of Trump has resulted in Europe's "worst economic nightmare."

The possibility of a new trade war could cause the euro zone economy to shift from slow growth to a recession. The German economy, which heavily depends on trade with the U.S., would be particularly affected by tariffs on European automobiles, according to a team of analysts led by James Knightley.

"Although European politicians assert readiness for a second Trump presidency, it is uncertain whether Trump can prompt greater integration due to the numerous domestic challenges faced by European governments. Europe will likely observe Trump's policies before taking action."

During the IMF annual meetings in Washington, D.C., last month, German Finance Minister Christian Lindner cautioned about the possibility of retaliation if the U.S. initiated a trade war with the European Union.

"To avoid a trade conflict with the European Union, it is crucial that diplomatic efforts are made to convince whoever enters the White House that it is not in the best interest of the U.S. Additionally, retaliation may have to be considered."