According to an advisor working closely with President-elect Donald Trump on his transition process, Trump has offered retired Lt. Gen Michael Flynn the influential position of national security adviser. (Video: Reuters / Photo: AP)

President-elect Donald Trump has asked Michael Flynn, a retired lieutenant general with a record of incendiary statements about Muslims, to be his White House national security adviser, a person close to the transition confirmed Thursday night.

At the same time, Trump is soliciting the help of Mitt Romney, a mainstream consensus figure who had been the face of the Republican resistance to Trump’s candidacy, in assembling his government.

Trump sought a meeting with Romney, scheduled for this weekend, to broker peace — and Sen. Jeff Sessions (R-Ala.), a vice chairman of Trump’s transition, told reporters that Trump could consider the 2012 GOP presidential nominee for an administration position, perhaps secretary of state.

The presence of Flynn and Romney in Trump’s orbit sends mixed signals to already jittery leaders around the globe, as well as officials in Washington’s foreign policy community, about the tone and substance of the Trump administration’s posture to the world.

Flynn, who would hold the most powerful national security position, is a retired three-star general and decorated intelligence officer who established a close relationship with Trump while campaigning at his side this year. His behavior and a string of controversial and dark statements about Islam, among other topics, have alarmed many of his former colleagues.

Sen. Jeff Sessions (R-Ala.), a vice chairman of President-elect Donald Trump’s transition team, and Kellyanne Conway, Trump’s campaign manager, speak to reporters at Trump Tower on Thursday. (Carolyn Kaster/AP)

Trump’s selection of Flynn, which was first reported by the Associated Press, comes after the president-elect enraged Democrats and civil rights groups by appointing Stephen K. Bannon, former chairman of Breitbart News, an alt-right news site that has become a forum for the white nationalist movement, as his chief strategist and senior counselor in the White House.

Flynn was widely expected to be tapped as national security adviser. A vice chairman of the transition team, Flynn has been a frequent presence at Trump Tower since the election. But the role of Romney was a surprising development, coming as Trump is expanding his outreach to foreign leaders.

On Thursday, he met with Japanese Prime Minister Shinzo Abe, who has been concerned by Trump’s negative campaign statements about Japan and his position against free trade. In a ­90-minute meeting in Trump’s New York apartment — attended by Flynn, Trump’s oldest daughter, Ivanka, and her husband, Jared Kushner — Abe sought assurances from the incoming U.S. president that he would maintain the long-standing alliance between the two nations.

The Trump-Romney relationship has been marked by acrimony: Trump has said Romney “walks like a penguin” and “choked like a dog,” while Romney labeled Trump “a phony, a fraud” who threatens national security.

But Romney is said to feel compelled by patriotic duty to answer Trump’s call for counsel, and he has long been animated by global affairs and enticed by a return to government service — even if he stops short of acquiescing and agreeing to join the Cabinet should Trump extend an offer.

“I think it’s good that the ­president-elect is meeting with people like Mr. Romney,” Sessions said. “He’s meeting with a lot of talented people that he needs good relationships with. I think Mr. Romney would be quite capable of doing a number of things, but he’ll be one of those I’m sure that’s reviewed, and Mr. Trump will make that decision.”

Sen. Jeff Sessions (R-Ala.) told reporters that the transition for President-elect Donald Trump was "working well together" and praised his decision to meet with former Republican presidential candidate Mitt Romney. He also said he would be "honored" to be considered for an appointment in Trump's new administration. (Video: Reuters / Photo: Jabin Botsford/The Washington Post)

Others close to the transition, however, said they doubted Romney ultimately would be in the mix for a Cabinet post.

Romney would be a more conventional choice than two others who are considered to be leading contenders to helm the State Department: former New York mayor Rudolph W. Giuliani and former ambassador to the United Nations John R. Bolton.

A fourth prospect, South Carolina Gov. Nikki Haley, was thrust into the mix for secretary of state after she met Thursday with the president-elect in his Trump Tower office. Haley, who is close with Vice President-elect Mike Pence, criticized Trump during the primaries but has since said she is encouraged by the promise of his presidency.

Calling Haley “unbelievably talented,” Trump transition spokesman Sean Spicer said on CNN: “Donald Trump right now isn’t looking to figure out who supported him and who didn’t . . . As long as they are committed to bringing change to Washington and making this country better, then they can be part of this team.”

Former House speaker Newt Gingrich, who had been considered a potential pick as secretary of state or another Cabinet position, announced Thursday that he had decided to serve Trump only as an outside adviser.

“I want to be free to network across the whole system and look at what we have to do to succeed,” Gingrich said Thursday when briefly reached by phone. Holding a Cabinet post, he said, would have been “not physically doable.”

The developments came on the same day that President Obama stood in Berlin with German Chancellor Angela Merkel to reassure Western allies about the United States’ commitment to NATO and other transatlantic partnerships.

Obama sounded notes of confidence that Trump recognizes the seriousness of the job before him, but he also challenged his successor to aggressively confront Russia.

During the campaign, Trump spoke admiringly of Russian President Vladi­mir Putin, and the two men spoke by phone on Monday. Obama — whose administration has accused Moscow of meddling in the U.S. elections by hacking the email of the Democratic National Committee — called on Trump to be “willing to stand up to Russia where they are deviating from our values and international norms.”

The U.S. posture with Russia is not only an area of disagreement between the 44th and 45th presidents, but also between Trump and Romney.

Trump has praised Putin as a stronger leader than Obama and vowed to work with Putin to fight Islamic State terrorists in Syria and elsewhere. Romney, meanwhile, has sharply condemned Putin, as have most Republican leaders.

In other respects, however, Romney would be a natural choice to lead Trump’s State Department. He has been an unrelenting critic of Obama’s foreign policy and of Hillary Clinton’s tenure as secretary of state. At a June 2015 summit he organized of business and political leaders in Park City, Utah, Romney presented a PowerPoint slide show assessing global hotspots that was titled: “The Most Consequential Obama Foreign Policy Mistakes.”

Romney’s meeting with Trump was an outgrowth of a phone call the two men had last Wednesday, the day after the election. Trump later tweeted, “Mitt Romney called to congratulate me on the win. Very nice!”

Similarly, Abe’s meeting with Trump came after the Japanese leader placed a congratulatory phone call to him. Abe, who was scheduled to travel through New York on his way to a regional economic summit in Peru, offered to meet with Trump, who quickly agreed.

Trump’s session with Abe raised questions among some in Washington’s foreign policy community because Trump apparently was not briefed by the State Department in advance. A former State Department official said such meetings normally would be preceded by numerous briefings for Trump from key diplomats — which is considered especially important here because the Japanese are concerned about comments Trump made on the campaign trail.

Tokyo fretted over Trump’s vow to kill the 12-nation Trans-Pacific Partnership trade accord that includes the United States and Japan, as well as his suggestions that the U.S. military basing agreements in Japan and South Korea are too costly to maintain.

“Trump said various things during his campaign, but I will not presuppose what he will do as president,” Tomomi Inada, Japan’s defense minister, said late last week.

Trump’s campaign manager, Kellyanne Conway, explained that the Trump-Abe meeting was designed to be informal because Trump has yet to assume office. “We are very sensitive to the fact that President Obama is still in office for the next two months,’’ Conway said.

Abe entered the meeting intent on emphasizing their common ground, including more robust U.S. defense spending and Japan’s role as the United States’ strongest ally in Asia.

“He’s going to work on chemistry and rapport and planting the idea that in the chaotic world that Trump is going to discover, Japan will be one of his best friends,” said Mike Green, an analyst at the Center for Strategic and International Studies who served as senior Asia director in the George W. Bush administration. “A lot of Asia, and I suspect the Europeans, too, are looking to Abe” for signals of how Trump intends to engage the world.

Trump has spoken with or met with several dozen foreign leaders and officials. Ron Dermer, the Israeli ambassador to the United States, appeared at Trump Tower on Thursday afternoon, but neither transition officials nor Israeli Embassy officials responded to questions about whether he met with Trump, someone else, or was just visiting.

With Conway by his side, Dermer told reporters that Israel had no doubt that Trump is “a true friend of Israel.” Pence, he said, “was one of Israel’s greatest friends in the Congress” and “we look forward to working . . . with all the members of the Trump administration, including Steve Bannon, and making the U.S.-Israel alliance stronger than ever.”

Asked why he had specifically mentioned Bannon, whose Breitbart News site has been decried as anti-Semitic by the Anti-Defamation League, Dermer did not respond.

Meanwhile, another ambassador in Washington, the United Arab Emirates’ Yousef al-Otaiba, noted in a CNN op-ed that Thursday was the United Nations-designated “International Day for Tolerance” and said that “divisiveness and polarization are on the rise across the world and — if left unchecked — this trend will undermine global stability and peace.”

Around the world, there is considerable anxiety about Trump’s presidency, and concerned and curious foreign leaders have rushed to establish contact with Trump and Pence.

Unless Trump schedules something earlier, his first international appearance will be at Group of 20 and NATO summits, both scheduled to be held next summer. But many world leaders are pushing for an earlier, up-close and personal sign that the new president wants to be a presence on the global stage.

Clinton had indicated that, if elected president, she would quickly convene NATO leaders for an informal gathering; the two most recent former alliance heads this week called on Trump to do the same.

Anders Fogh Rasmussen and his predecessor, Jaap de Hoop Scheffer, also warned the president-elect against undermining U.S.-European policy on Ukraine by making an early deal with Putin.

Having expected, like most U.S. pollsters, a Clinton victory, U.S. allies are shifting gears to ready for what one senior European diplomat called “an earthquake, politically speaking, for the transatlantic alliance.”

Greg Miller and Jerry Markon contributed to this report.