"We will hand over 13 of our MiG-29 jets to Ukraine," Slovak premier Eduard Heger told journalists, adding that Bratislava would also deliver a Kub air defence system to Ukraine.

"We're giving these MiGs to Ukraine so that it can protect civilians against the many bombs that fall on their houses and which are the reason why people are dying in Ukraine," Heger said.

Ukraine has long requested fighter jets from Western allies, although seeking primarily modern US-made F-16s.

"Our steps are fully coordinated with Poland and Ukraine," Heger said, adding that his government "stands on the right side of history".

He said Slovakia will receive compensation for the donation from the European Peace Facility, the EU's Ukraine fund.

"There is also a bilateral offer from the US regarding a particular military system to be donated to Slovakia whose value for the Slovak Republic will be approximately $700 million," Defence Minister Jaroslav Nad said, without providing details.

"We are talking about 900 million (euros) altogether," he added.

The Kremlin in response on Friday said the fighter jets given to Ukraine by Poland and Slovakia would be destroyed, and repeated that Western arms deliveries to Kyiv would not change Russia's military aims.

"The supply of this military equipment -- as we have repeatedly said -- will not change the outcome of the special military operation... Of course, all this equipment will be destroyed," Kremlin spokesman Dmitry Peskov told journalists, using the official term for Moscow's military intervention.

Polish President Andrzej Duda on Thursday announced that Warsaw would send four Soviet-made MiG-29 jets to Ukraine "in the coming days".

- 'Do more to help' -

Fellow staunch Ukraine supporter Estonia on Friday applauded the decision to send planes.

"Slovakia & Poland show great leadership by sending requested fighter jets to Ukraine," Estonia's defence ministry said on Twitter.

"We need to do more to help Ukraine win and defeat the aggressor," it added.

Nad said the transfer of MiGs from Slovakia to Kyiv will take "a couple of weeks".

The Slovak batch will include 10 operational MiG-29 fighter jets and an additional three that have not been operational since 2008.

"At least three jets will only be used as spare parts," General Daniel Zmeko, chief of the general staff of the Slovak armed forces, told reporters.

Slovakia also has one other MiG-29 that will be placed in a military museum at home.

The country plans to replace the jets with American F-16s. The changeover should take place no later than January 2024.

Slovakia opted to stop using its MiGs last year since they were dependent on Russian technicians and companies.

The Czech Republic and Poland have since been protecting its airspace.