The European Union's foreign policy chief slammed the U.S.'s so-called Middle East peace plan Sunday during a visit to Jordan's capital.

"The U.S. plan challenges many of the internationally agreed parameters: the 1967 border, as agreed by both parties, with a state of Israel and an independent, viable state of Palestine, living side-by-side in peace, security and mutual recognition," said Josep Borrell, who met with Jordanian Foreign Minister Ayman Safadi and King Abdullah in Amman to discuss bilateral relations and regional developments.

"In Jordan and the European Union, we are very much aware that the Israeli-Palestinian conflict is one of the longest, most painful and complex conflicts in our history.

"The experience over the past 50 years has shown that without agreement among all sides, no peace plan has the chance to succeed. To find a sustainable way forward, both parties need to come back to the table," Borrell said later in a statement to Jordanian television.

Borrell also commented on Twitter.

"Had a frank discussion with @AymanHsafadi on the Middle East Peace Process #MEPP.

"The EU and Jordan share the commitment to a two-state solution and respect for international law. We need solutions that can be accepted by both parties in this long-lasting conflict."

On Tuesday, U.S. President Donald Trump announced his so-called peace plan to end the Israeli-Palestinian conflict during a press conference at the White House alongside Israeli Prime Minister Benjamin Netanyahu. No Palestinian representatives were present.

During the event, Trump referred to Jerusalem as "Israel's undivided capital."

The so-called "Deal of the Century" unilaterally annuls previous UN resolutions on the Palestinian issue and suggests giving Israel almost everything they have been demanding.