WASHINGTON (Reuters) - After years of rising U.S.-Russia tensions over Ukraine, Syria, cyber attacks and nuclear arms control, Donald Trump’s election as U.S. president may offer a narrow window to repair relations as he and Russian President Vladimir Putin size up each other.

U.S. President-elect Donald Trump speaks at election night rally in Manhattan, New York, U.S., November 9, 2016. REUTERS/Mike Segar/File Photo

But Trump’s ascent to the White House carries the risk of dangerous miscalculation if the U.S. president-elect and Putin, two willful personalities and self-styled strong leaders who have exchanged occasional compliments, decide they have misjudged one another, according to Russia experts and others.

U.S. officials and private analysts predict that Putin, who has reasserted Moscow’s military and political muscle from eastern Europe to the Middle East, will avoid openly provoking Trump before he takes office.

“Putin has the ability to advance his interests in many different ways. Sometimes tactical diplomacy can help,” said Fiona Hill, a senior fellow at the Brookings Institution, a Washington think-tank.

“We’re in temporary truce phase,” said Hill, who has served as the U.S. national intelligence officer for Russia and Eurasia in the George W. Bush and Obama administrations and co-authored a book on Putin.

Michael McFaul, a former U.S. ambassador to Moscow under President Barack Obama, said Putin likely will wait to see if he can reach some accommodation with Trump to allow the lifting of Ukraine-related sanctions imposed by Washington and the European Union that have contributed to Russia’s growing economic woes.

During the campaign, Trump was criticized by his Democratic Party rival, Hillary Clinton, for praising Putin as a strong leader and saying ties with Russia should be improved at a time when Moscow and Washington are at odds over Syria and Ukraine.

Trump rattled Washington’s European allies with comments questioning NATO’s mutual self-defense pledge and suggesting that he might recognize Russia’s 2014 annexation of Ukraine’s Crimea region.

Putin last year called Trump “a really brilliant and talented person” and the Kremlin said on Thursday that the U.S. president-elect’s foreign policy approach was “phenomenally close” to that of the Russian leader.

Putin “has a future president who has expressed a desire to cooperate, who has expressed a desire to move away from the Obama policies. Why would you screw that up with a provocation?” asked McFaul, now at Stanford University.

In Syria, a U.S. official said, Putin appears to be extending a “humanitarian” pause in air strikes against moderate rebels holding the eastern side of Aleppo to give Trump an opportunity to affirm the willingness he expressed during the campaign to seek a more cooperative U.S.-Russian relationship.

“I think they were holding their fire for the purpose of decreasing the international pressure on them, and now, like the rest of the world, they may be taking stock of the current situation,” said the official, speaking on condition of anonymity.

But U.S. officials caution that Russia still may feel compelled to launch more attacks after dispatching a naval task force led by the aging aircraft carrier Admiral Kuznetsov to the eastern Mediterranean in a show of force.

CONFLICT IN CYBERSPACE

The U.S. government has publicly accused Moscow of hacking the Democratic National Committee and other party organizations during the election campaign, which Russia has denied. Trump declined to blame Russia, and the Election Day Russian cyber attacks that some officials feared never materialized.

Trump has not laid out a detailed Russia policy, and many in his party, including potential top advisors and cabinet officials, have taken a hawkish view of Moscow.

Former House of Representatives speaker Newt Gingrich, a Trump ally rumored for a senior post, lambasted in 2014 what he called Obama’s weak response to Russia’s land-grab in Ukraine. Putin, Gingrich wrote, is “a ruthlessly determined leader motivated by nationalism and an imperial drive.”

And while there was celebration in Moscow after Trump’s victory over former secretary of state Clinton, who has been sharply critical of Putin, some Russians cautioned against euphoria.

“The idea that it will be easier to strike a deal with Trump than Clinton is wrong. ... Everything will be tested when we get down to business,” analyst Vladimir Bruter told the daily pro-Kremlin tabloid Komsomolskaya Pravda before Tuesday’s election.

Some experts and U.S. officials say there is a high risk of miscalculation or even confrontation, given Trump’s history of taking slights and challenges personally.

“That’s actually where reality is going to intrude,” Hill said. “Putin’s pretty thin-skinned, too.”

Putin has a penchant for challenging adversaries, particularly when he senses weakness, and he has long made it clear that he intends to reassert what he considers Russia’s rightful global role.

Suspending a treaty with Washington on cleaning up weapons-grade plutonium last month, Putin listed conditions for resuming Russian participation that amounted to a laundry list of grievances against the United States.

The demands included lifting Ukraine-related U.S. economic sanctions, compensating Moscow for those sanctions and reducing the U.S. military presence in NATO’s eastern European states to the levels of 16 years ago.

Russia’s bedrock concern “is whether they believe the threat of U.S.-promoted regime change is abating under a President Trump,” said Andrew Weiss, vice president for studies at the Carnegie Endowment for International Peace. “Everything else is a secondary, lower-order problem.”

Putin has accused the U.S. government of promoting widespread street protests in Russia following its 2011 elections, as well as the “color revolutions” in Georgia, Ukraine and elsewhere.

On specific issues, Weiss said, there are few if any easy opportunities for rapid U.S.-Russian agreements.

“The agenda’s really threadbare,” he said. “We’re basically at a standstill.”

(This version of the story fixes a typo in paragraph two)