By Simon Lewis and Steve Holland

WASHINGTON (Reuters) - This was a disorienting week for those anxious over how the new Trump administration will fulfill Donald Trump's vow to end the Ukraine war.

As the U.S. president took his first steps toward diplomacy over the nearly three-year conflict, comments from his top officials left many unsure what he has planned for the biggest security crisis to face Europe in decades.

Trump spoke to Russian President Vladimir Putin and Ukraine's Volodymyr Zelenskiy by phone on Wednesday and tasked officials with kickstarting negotiations, adding that a summit with Putin in Saudi Arabia was likely.

The calls blindsided European allies already wondering what to make of comments from Trump's defense secretary, Pete Hegseth.

Hegseth told NATO allies earlier on Wednesday that it was unrealistic for Ukraine to join the alliance as part of a negotiated settlement with Russia, that Kyiv's hopes of restoring its 2014 borders were an "illusionary goal," and that the United States would not send troops as part of a security force in Ukraine.

He appeared to backtrack on his own remarks the next day, telling a press conference that "everything is on the table" for Ukraine war negotiations.

On Friday, Vice President JD Vance sowed more confusion, suggesting in a Wall Street Journal interview that the U.S. would reserve options for pressuring Moscow, including sending U.S. troops to Ukraine, which would be a major shift from former President Joe Biden's policy of keeping American forces off the battlefield there.

Vance later said on X the Journal had twisted his words, saying "American troops should never be put into harm's way where it doesn't advance American interests and security."

Ambassador Daniel Fried, a retired U.S. diplomat now with the Atlantic Council think tank, said the administration's messaging had been contradictory but that officials had left themselves room to negotiate an acceptable outcome with Russia.

"They're all over the map, they have trouble getting a disciplined line, but they haven't ruled anything out. They've covered the position in a cloud of ambiguity and uncertainty," he said.

CONCESSIONS TO PUTIN?

The administration's comments left the impression among some European allies that the Trump administration was making concessions to Putin before any negotiations had taken place.

German Defense Minister Boris Pistorius on Friday called the administration's approach "clumsy" and "a mistake."

Putin had "not budged an inch" on his negotiating position so it was not in the West's interests to do so, he said at the Munich Security Conference, where defense officials and diplomats gathered this week.

"It would have been much better to talk about possible NATO membership and territorial changes at the negotiating table," Pistorius said.

Republican U.S. Senator Roger Wicker, who chairs the Senate's Armed Services Committee, slammed what he called a "rookie mistake" by Hegseth to apparently cede Ukraine's border before negotiations have begun, adding he was "puzzled" and "disturbed" by Hegseth's comments.

"Everybody knows ... and people in the administration know you don't say before your first meeting what you will agree to and what you won't agree to," Wicker told Politico on Friday.

There were also questions over who would carry out Trump's Ukraine policy. He named in a social media post negotiators including Middle East envoy Steve Witkoff, who flew to Russia on Tuesday to conduct a prisoner swap, but leaving out Ukraine envoy Keith Kellogg.

The White House later clarified that Kellogg was still involved in Ukraine policy.

Fried said that despite the confused messaging, Trump's priorities on Ukraine were coming into view and could lead to a "good outcome" for Ukraine. Those priorities appeared to be securing a ceasefire quickly, that Ukraine must have security guarantees and that European rather than U.S. troops would be on the ground to secure the peace, Fried said.

"A good outcome means the war stops, 80% of Ukraine is free, and there are security guarantees for Ukraine sufficient that Russia won't start the war again. That is a strategic victory for Ukraine," Fried said.

(Reporting by Simon Lewis and Steve Holland; additional reporting by Trevor Hunnicutt; Editing by Don Durfee and Rosalba O'Brien)