The White House is planning for a possible trilateral meeting between the U.S., Russian and Ukrainian presidents in the Hungarian capital of Budapest as the next step in negotiating an end to the years-long war, according to a Trump administration official and a person close to the administration.

The U.S. Secret Service is preparing for the summit in the Central European nation led by Prime Minister Victor Orbán, who has been close with President Donald Trump since the American president’s first term in office.

A spokesperson for the White House did not immediately respond to a request for comment.

While the Secret Service often scouts multiple locations and the ultimate venue could change, Budapest is emerging as a first choice for the White House, said the two people, both granted anonymity to discuss private conversations. Russian President Vladimir Putin told Trump he preferred Moscow and French President Emmanuel Macron pushed for Geneva as ideal meeting spots. Not to be left out, the Swiss foreign minister promised “immunity” to Putin for an outstanding war crimes warrant if the nation known for neutrality was chosen for peace talks.

Hungary would be an uncomfortable choice for Ukraine as it harkens back to the 1994 Budapest Memorandum, which the U.S., the United Kingdom and Russia promised to uphold Ukraine’s independence, sovereignty and respect for its border in exchange for relinquishing its nuclear weapons. Putin’s 2014 assault on Ukraine proved the agreement meaningless when none of the signatories provided military forces to counter the attacks.