The Central European countries, which spent four decades under Moscow's rule following World War II, have provided substantial military aid to Ukraine and welcomed more than a million war refugees since Russia's invasion last year.

But general elections scheduled for September 30 in Slovakia and October 15 in Poland have taken a toll on that staunch support as fatigue with war aid grows among the people.

Polish Prime Minister Mateusz Morawiecki said on Wednesday that his country was "no longer transferring weapons to Ukraine because we are now arming Poland with more modern weapons."

And former Slovak defence minister Jaroslav Nad said in Prague on Thursday that his country would stop direct arms supplies and curb NATO supplies via its territory if veteran leftwinger Robert Fico became prime minister.

Morawiecki's statement raised eyebrows in Ukraine and elsewhere because Poland had so far been a star helper.

But other Polish politicians were quick to adopt a more conciliatory tone, with the president arguing that the remarks had been taken the wrong way.

"Polish-Ukrainian relations have become hostage to the Polish electoral campaign," Piotr Buras from the European Office on Foreign Relations told AFP.

He added that the struggle for votes between the ruling conservative Law and Justice (PiS) party and the far-right was "damaging Poland's image as an unequivocal supporter of Ukraine and risks a deterioration of bilateral relations".

- 'Very political' -

Pavel Havlicek, an analyst at Prague's Association for International Affairs, also blamed the elections.

"The statement was very political and aimed at Polish society. But it did not mean Poland would give up on its obligations," he told AFP.

In fact, government spokesman Piotr Muller promised Poland would "carry out previously agreed deliveries of ammunition and armaments."

Morawiecki's statement also caused a stir because Poland, alongside regional peers Slovakia and Hungary, is currently embroiled in a rift with Ukraine over grain.

Kyiv is suing the three countries at the World Trade Organisation (WTO) after they unilaterally banned grain imports from Ukraine in a bid to protect their farmers.

Czech independent military analyst Jiri Vojacek said he expected Polish supplies to continue as Poland still has weapons to send.

"Of course they have less to offer than when the war started. But as far as I know, the supplies persist. The organisations that were in charge of them are carrying on," he told AFP.

"So they have to live with that statement until the election and then they will give the green light again."

In Slovakia, Poland's southern neighbour, only 40 percent of people believe Russia is responsible for the war, according to a poll by the Globsec think tank.

- 'Less useful' -

Fico, the former Slovak premier whose Smer-SD party is tipped to win the election, has vowed to stop all military aid to Ukraine if he wins.

"It only extends the war and the suffering of civilians without changing the standpoint of the Russian Federation," reads Smer's election programme.

Slovakia has provided Ukraine with military equipment including Russian-made warplanes and a rocket system, besides repairing arms used by Ukrainian soldiers.

Former minister Nad, the first NATO politician to send fighter jets to the Ukrainian battlefield, told AFP that Fico should be taken seriously.

"If he becomes prime minister, it is most probable" that he will stop arms supplies to Ukraine and even curb NATO supplies via Slovak territory, he said.

"If he succeeds in the election, it will be because he is staunchly pro-Russian and staunchly anti-Ukrainian... so he can't change that view."

Both Poland's PiS and Slovakia's Smer might find it difficult to form a government after the election, according to polls signalling a possible stalemate in both countries.

"The formation of government will be difficult and a snap election in spring 2024 cannot be ruled out," Buras said about Poland, warning that Warsaw may therefore stick to its "assertiveness" on Ukraine after the October vote.

Kyiv, on the other hand, might look for partners elsewhere.

"Poland is less useful for Kyiv than in the past," Buras said.