President Trump on Wednesday taunted Russia for backing a “Gas Killing Animal” and defied a threat from Moscow that it would shoot down US missiles over Syria, warning, “They will be coming.”

But that was so 40 minutes ago.

“Russia vows to shoot down any and all missiles fired at Syria. Get ready Russia, because they will be coming, nice and new and ‘smart! ’ ” Trump first wrote on Twitter.

“ You shouldn’t be partners with a Gas Killing Animal who kills his people and enjoys it! ”

Trump appeared to be reacting to comments from the Russian ambassador to Lebanon, Alexander Zasypkin, who said that Moscow would intercept any rockets fired into Syria.

Then, about 40 minutes later, Trump took a conciliatory turn.

“Our relationship with Russia is worse now than it has ever been, and that includes the Cold War. There is no reason for this,” Trump tweeted.

“Russia needs us to help with their economy, something that would be very easy to do, and we need all nations to work together. Stop the arms race? ”

Continuing his shift, Trump then blamed the icy relationship between the superpowers on special counsel Robert Mueller’s probe into Moscow’s involvement in the election.

“ Much of the bad blood with Russia is caused by the Fake & Corrupt Russia Investigation, headed up by the all Democrat loyalists, or people that worked for Obama,” he tweeted. “Mueller is most conflicted of all (except Rosenstein who signed FISA & Comey letter). No Collusion, so they go crazy!”

Both Mueller and Deputy Attorney General Rod Rosenstein, who’s oveseeing the investigation, are Republicans.

The president has been huddling with military leaders and talking to France and Britain on developing a “forceful” response to Saturday’s chemical attack in Douma, Syria, which killed at least 60 civilians.

Trump blamed Syrian strongman Bashar al-Assad and Russian President Vladimir Putin, who has been a supporter of the Syrian regime, for the attack.

Putin, at a Kremlin appearance for new foreign ambassadors to Moscow, did not directly respond to Trump’s threats but told the diplomats that the “state of things in the world cannot but provoke concern.”

“The situation in the world is increasingly chaotic,” he said.

“Nevertheless, we hope that common sense will prevail in the end and that international relations will become more constructive — that the whole global system will become more stable and predictable.”

Earlier, Kremlin spokesman Dmitry Peskov wouldn’t comment on Trump’s statements.

“We do not participate in Twitter diplomacy,” he said.

Asked what “get ready Russia” means, White House press secretary Sarah Huckabee Sanders responded, “There’s a lot there that you can read from. But at the same time, the president has a number of options at his disposal, and all of those options remain on the table and we continue to look at each one of them.”

Meanwhile, the Kremlin and Syria began taking actions on land and sea to prepare for an assault.

A top Russian lawmaker, Alexei Kondratyev, said that in addition to its ground-based air defense systems in Syria, Russia will use warships in the Mediterranean Sea to protect its assets in the region.

And Zasypkin, the Russian ambassador to Lebanon, said Moscow’s actions could go further than just intercepting rockets.

“If there is a strike by the Americans, then the missiles will be downed and even the sources from which the missiles were fired,” he said in an interview on Tuesday with a television station linked to Hezbollah.

That could lead to a possible conflict at sea because the cruise missiles Trump used to strike a Syrian airfield last April were launched from American warships.

Lt. Gen. Viktor Poznikhir, of the Russian military’s General Staff, said Russian military police will head to Douma on Thursday to provide security — putting them on the ground where a possible US retaliatory strike could occur.

And Syria, in anticipation of an attack, began moving warplanes to a Russian base, The New York Times reported.

A US pinpoint strike on Syrian targets that does not harm Russian personnel “will allow Trump to say that the Assad regime has paid a heavy price . . . and Russia, in its turn, will be able to limit itself to ringing statements,” said Fyodor Lukyanov, the head of the Council for Foreign and Defense Policies, an association of top Russian political and security experts.

He added, however, that the United States would be unlikely to warn Russia of the coming strike this time.

“The context of the relations has changed radically in the past year: We’re in a state of a real and tangible Cold War,” Lukyanov said.

In Russia, the headlines portrayed Trump as the antagonist.

“Is macho Trump going to start World War III?” Russia’s best-selling newspaper, Komsomolskaya Pravda, blared on Wednesday.

With Wire Services