Donald Trump
Donald Trump suggested the US should fire at Russian planes for 'dangerous' barrel rollsChip Somodevilla/Getty Images

Republican presidential frontrunner Donald Trump has said the US has "gotta shoot down" Russian planes if diplomacy doesn't work. Trump's comments came just days after a Russian plane performed a move criticised by the Pentagon as 'dangerous' when it barrel-rolled over a US plane for the second time in a month.

The aggressive move was performed over the Baltic Sea, where Russian jets buzzed a US Destroyer ship repeatedly several days before the latest incident.

In an interview on Indiana radio show Fort Wayne's Morning News, Trump said: "I think it's terrible, I mean I watched it. It just shows how low we've gone where they can toy with us like that.

"Normally, Obama, let's say a president, because you want to make at least a call or two right, but normally Obama would call up Putin and say, 'Listen, do us a favour, don't do that, get that maniac, just stop it.' But we don't have that kind of a president. He's gonna be out playing golf or something."

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Trump's burgeoning mutual appreciation of Putin, which has seen the Republican candidate hint at warmer relations with Russia if he wins the nomination and goes on to be president, saw him suggest Obama should have approached Putin over the incidents.

"I don't know, at a certain point, you can't take it, I mean, at a certain point, you have to do something that, you just can't take that," he said.

"That is not right. It's against all, you know, when you talk about Geneva Convention, there's gotta be things that are against it. You can't do that. That's called taunting. But it should certainly start with diplomacy and it should start quickly with a phone call to Putin, wouldn't you think?"

However, when push came to shove, Trump said the US should shoot at a plane in the same situation if diplomacy didn't work.

"And if that doesn't work out, I don't know, you know, at a certain point, when that sucker comes by you're gonna shoot. You're gonna shoot," he said.

"And it's a shame. It's a shame. It's a total lack of respect for our country and it's a total lack of respect for Obama. Which as you know, they don't respect."

Update: Original headline amended to use correct word 'diplomacy'.