President Vladimir Putin will probably retaliate after President Trump canceled a weekend meeting in Argentina over Russia’s detention of Ukrainian sailors, Russia veterans said after the surprise announcement Thursday.

About an hour after saying he "probably" would meet Putin at the G-20 summit in Buenos Aires, Trump tweeted that he would cancel the meeting “[b]ased on the fact that the ships and sailors have not been returned to Ukraine,” surprising critics who accused him of being soft on Putin.

But the snub — the second this month, after a Paris meeting also was scrapped — may provoke Putin in the near-term, rather than steer his actions toward U.S. interests.

“Watch for prolonging the detention of the Ukrainian sailors and ships,” said Alexander Vershbow, U.S. ambassador to Russia during Putin’s early years in power, from 2001 to 2005. “He will show he's tougher,” Vershbow said about Putin.“Russians are playing down the cancellation, but I’m sure they are angry. I’m frankly surprised Trump did it," he said.

Nina Khrushcheva, a New School international affairs expert and granddaughter of Soviet leader Nikita Khrushchev, said Trump’s decision to punish Putin is notable after his decision last week not to punish Saudi Arabia’s Crown Prince Mohammed bin Salman after the CIA determined he likely ordered the murder of dissident Jamal Khashoggi.

“When Putin realizes he has been duped by Trump's false niceties, and Trump's approach to Russia is based on an idea that only America can act with impunity versus the rest and is fully in line with his predecessors, Putin's reaction will unlikely be pretty,” Khrushcheva said.

Khrushcheva believes Trump's evolving approach toward Putin reflects a belated adoption of “the Washington consensus” that “Putin should not get above his station as a secondary power and should not act as it pleases.”

Trump's move followed a politically explosive first summit with Putin in Helsinki, where Trump appeared to accept Putin's denial of hacking Democrats during the 2016 election. It came hours after Trump's former attorney Michael Cohen agreed to plead guilty to lying to Congress about a planned Trump hotel in Moscow, as part of special counsel Robert Mueller's investigation of possible Trump campaign collusion with Russia.

Vershbow, who believes Trump’s behavior at the July summit in Helsinki was an "embarrassing performance," said the cancellation likely reflects guidance from Secretary of State Mike Pompeo, who briefed Trump on Air Force One, that “the timing and optics could be awkward" less than a week after naval incident with Ukraine began.

But Vershbow said by canceling the meeting, Trump has missed opportunity to pressure Putin to abandon separatists in eastern Ukraine and to discuss the Intermediate-Range Nuclear Forces Treaty, which Trump is moving to repudiate, potentially lifting nuclear weapon restrictions in Europe.

Although some experts believe Putin is likely to lash out in response to the meeting cancellation, Hudson Institute senior fellow David Satter said he doubts the news will meaningfully worsen Putin's conduct.

"They will not do anything they would not have done anyway. Trump is right to set limits to our tolerance of the encroachments by Russia in the right of free navigation," said Satter, a former journalist expelled from Russia in 2013.

"These meetings are more important to Putin than they are to us," Satter said. "If Trump had proceeded with the meeting it would have suggested that relations with Russia are too important for the U.S. to react to Russian violations. By canceling it, we drive home the opposite message and give the Russians an incentive to behave a little bit better in the future."