Austria, Romania, Hungary and the Czech Republic have accepted the invitation extended by Israel's Ministry of Foreign Affairs to attend the reception Sunday in honor of the U.S. embassy's move to Jerusalem.

Bulgaria, which previously said its ambassador would attend the event, has now given the Foreign Ministry an unclear answer.

The five countries are all members of the European Union, which has been leading a policy against the embassy's move. According to the EU's policy, Jerusalem will be the capital of Israel and Palestine in the framework of a future two-state solution.

>> Everything you need to know about the U.S. embassy in Jerusalem >>

Following U.S. President Donald Trump's announcement that the U.S. would move its embassy, EU official Donald Tusk said leaders of the 28-nation bloc reiterated their "firm commitment" to a two-state solution for Israel and the Palestinians. Although Tusk did not mention Trump by name, his remark amounted to a rebuke of the announcement.

Twelve states declined the invitation to Sunday's event, some for technical reasons and others on principle, such as Russia, Germany, Ireland, Malta, Mexico, Portugal, Australia, Poland and Sweden.

The event will take place on Sunday evening in Jerusalem, a day before the official relocation ceremony, which will be attended by Trump's daughter and adviser, Ivanka Trump, his son-in-law and adviser, Jared Kushner, U.S. Secretary of the Treasury Steven Mnuchin and other elected U.S. officials.

U.S. Ambassador to Israel David Friedman said on Friday that the decision to move the American embassy to Jerusalem wasn't made as part of a "give and take" with Israel, but rather based on "the interests of the United States."

Meanwhile, the IDF is preparing for mass protests on Monday, the day the U.S. embassy moves, and the day after, when Palestinians mark the 70th anniversary of the Nakba. A senior army source warned that the upcoming demonstrations will be significantly more violent than those on the Gaza border in recent weeks.