Meeting would bring to the international stage one of the world’s most enigmatic political relationships

WASHINGTON—The White House is planning for a potential summit between President Donald Trump and President Vladimir Putin of Russia, according to people familiar with the efforts, a meeting that would bring to the international stage one of the world’s most enigmatic political relationships.

A senior administration official said Friday that Jon Huntsman, the U.S. ambassador to Russia, has been in Washington to help arrange a meeting between Messrs. Trump and Putin.

The planning is still at an early stage, the official said, with the two nations needing to agree on a date and location.

“This has been an ongoing project of Ambassador Huntsman, stretching back months, of getting a formal meeting between Putin and Trump,” the official said.

Any meeting between the two presidents would be expected to include discussions on Syria, Ukraine and nuclear-arms control. The summit’s purpose would be to resolve longstanding differences, people familiar with the matter said.

The summit would mark the third meeting between Messrs. Trump and Putin, who held discussions on the sidelines of two international meetings in 2017—one at the Group of 20 summit in Germany last July and at a November summit in Vietnam.

The potential meeting comes as special counsel Robert Mueller continues to investigate alleged Russian interference in the 2016 presidential election and whether associates of Mr. Trump colluded with Moscow. Mr. Trump has denied any collusion and has described the probe as a “witch hunt.” Russia has denied meddling in the election.

Asked about a summit taking place amid Mr. Mueller’s investigation, another administration official said, “Of course there are discussions of the political perception.”

In April, Yuri Ushakov, a former Russian ambassador to the U.S. and now an aide to Mr. Putin, said Mr. Trump had invited Mr. Putin to Washington during a March 20 phone call.

White House press secretary Sarah Sanders, responding to questions about Mr. Ushakov’s revelation, confirmed the invitation. “The two had discussed a bilateral meeting in the ‘not-too-distant future’ at a number of potential venues, including the White House,” Ms. Sanders said at the time.

Russian Foreign Minister Sergei Lavrov told a Russian news agency in late April that “President Putin is ready for such a meeting.”

Mr. Trump is currently focusing on the summit with Kim Jong Un, the North Korean leader, according to an administration official. “If negotiations there continue, [work on the Russia summit] will be delayed,” the official said.

The Russia summit “will be focused on specifics, not grand bargaining,” the official said. “Those things need to be negotiated.”

Before any summit takes place, a meeting is likely to occur between Gen. Joe Dunford, the chairman of the Joint Chiefs of Staff, and Gen. Valery Gerasimov, the chief of the Russian General Staff, the official said. These talks would focus on de-escalation of the conflict in Syria.

Mr. Trump has long said he wanted to improve relations with Russia, while at the same time bemoaning the poor state of Russian-U.S. ties.

As president-elect in January 2017, he made clear he wanted a cordial relationship with Mr. Putin. “If Putin likes Donald Trump, I consider that an asset, not a liability, because we have a horrible relationship with Russia,” Mr. Trump said at a news conference.

Three months ago, after he spoke to Mr. Putin on the phone and congratulated him on his election victory, Mr. Trump tweeted that “Getting along with Russia (and others) is a good thing, not a bad thing…”

The following month, though, he wrote in a tweet that “our relationship with Russia is worse now than it has ever been, and that includes the Cold War.”

He added: “There is no reason for this. Russia needs us to help with their economy.” He went on to suggest that a more collaborative relationship with Russia could curb the arms race.

As he has sought better ties with Moscow, Mr. Trump has been shadowed by the investigation into alleged Russian interference in the 2016 presidential race.

Mr. Mueller has been questioning former Trump aides and associates about whether the campaign colluded with Russia in an effort to defeat Democratic nominee Hillary Clinton. Mr. Mueller is also examining whether the president obstructed justice in firing former FBI Director James Comey ; Mr. Trump has denied any obstruction of justice.

Meeting Mr. Putin last year on the sidelines of a G-20 summit meeting in Germany, Mr. Trump voiced concerns about Russian interference in the election, then-Secretary of State Rex Tillerson said at the time. Mr. Putin, during a two-hour meeting that lasted twice as long as planned, denied any involvement.

At the meeting in Vietnam, also on the sidelines of a summit meeting, Mr. Putin reiterated that his country didn’t meddle in the U.S. elections.

On Air Force One, Mr. Trump said: “He said he didn’t meddle. I asked him again. You can only ask so many times.”

Former presidents George W. Bush and Barack Obama each held summits with Mr. Putin within six months of taking office. Mr. Trump has now been in office more than 16 months.