​Slovakia’s defense minister said Thursday that his country would be willing to send Ukraine highly sought-after S-300 ​long-range ​air defense systems if NATO ​provides a replacement​ — only for Defense Secretary Lloyd Austin​ to leave him hanging by saying he had nothing to announce. ​​

Jaroslav Nad ​said Slovakia has been in discussions with the US, Ukraine and NATO “on the possibility to deploy, send, or give the S-300 to Ukraine.”

​”We are willing to do so immediately when we have a proper replacement​,” ​Nad told reporters at a joint press conference with Austin in Bratislava. 

“The only strategic air defense system that we have in Slovakia is the S-300 system,” ​he said, referring to the Soviet-era surface-to-air system​ that would give the Ukrainian military the capability to target Russian ballistic missiles and high-flying warplanes. 

But Nad said he was worried about leaving a defense gap in his country, a NATO member bordering Ukraine, once the advanced weapons system is shipped out. 

​”​I’m defense minister to ​S​lovak​ia, my first responsib​i​lity is to do everything ​I am capable ​of ​to guarantee ​the defense and security of our people and our territory​,” he said.​

But Austin was noncommittal about providing a replacement.

“I don’t have any announcements for you this afternoon,” he said. “These are things that we will continue to work with all of our allies on. And certainly this is not just a U​S​​ issue, it’s a NATO issue.”

Ukrainian President Volodymyr Zelensky on Wednesday pleaded with the US to either establish a no-fly zone over his country, a situation that President Biden has said would escalate the war, or provide missile systems like the S-300 to protect his people from attacks by Russian planes and long-range rockets. 

“You know what kind of defense systems we need, S-300 and other similar systems​,” he told members of Congress, before raising the stalled transfer of more than two dozen Polish MiG-29 fighter jets.

“You know how much depends on the battlefield on the ability to use aircraft … to protect our people, our freedom, our land, aircraft that can help Ukraine, help Europe,” he said. “And you know that they exist, and you have them, but they are on earth, not in Ukraine — in the Ukrainian sky. They do not defend our people.”

Poland offered to shift 28 of the Soviet-era jets to the US air base in Ramstein, Germany, but the Biden administration rejected the proposal over fears Russian President Vladimir Putin would view the planes as a provocation and escalate the war, potentially setting off World War III.​

Earlier in the presser, Austin said Ukrainian forces have been able to prevent Russia from establishing air superiority through the air defense systems the US and NATO allies have already supplied. 

“O​u​r goal has been to continue to reinforce those things that have worked for the ​Ukrainian forces​,” he said. “So we are talking to a number of our a​l​lies and partners to ensure we get as much capability as we can to continue to provide help to the Ukrainian forces​.”

​​In a Defense Department briefing on Wednesday, a ​senior official played down the possibility of sending an S-300 system to Ukraine. 

“​We are talking to allies and partners about providing the Ukrainians some systems that we know they know how to use, that they’re already trained and equipped to use, that they are using with effect. And that, you know, we ourselves necessarily wouldn’t be the best donor for​,” the official said. ​​

Get the latest updates in the Russia-Ukraine conflict with The Post’s live coverage.

On Wednesday, Biden announced an additional $800 million in military aid to Ukraine that includes a variety of air defense systems, drones, Javelin anti-tank missiles, Stinger anti-aircraft missiles, heavy armor and ammunition — but not an S-300, which can hit targets at a longer range or higher altitude than the Stingers. 

With Post wires