Miloš Zeman made the declaration during a meeting with Polish President Andrzej Duda on Tuesday, public broadcaster Polish Radio’s IAR news agency reported.
The two heads of state and their wives met for talks in the Czech town of Náchod, close to the Polish border.
During a joint news conference with Duda, Zeman said that the Czech Republic was ready to fulfil its commitments as a NATO member.
'We would be obligated to help, and would do so willingly'
He said: “It’s obvious to me that if Russia - who else - attacked Poland, the Baltic states or any other NATO member country, then in line with Article 5 of the North Atlantic Treaty [on collective defence], and for reasons of self-preservation, we would be obligated to help, and would do so willingly.”
Zeman distanced himself from a controversial statement two days earlier by Andrej Babiš, a former Czech prime minister who is now running for the country’s presidency.
During a television debate on Sunday, Babiš said that if neighbouring Poland or the Baltic states were attacked, he would not send Czech troops to help defend these countries, according to news reports.
Zeman on Tuesday called Babiš’s remarks “misguided and unconsidered,” saying that they were uttered "in the heat of the presidential campaign."
NATO's Article 5 is 'binding’: Polish president
Meanwhile, Poland’s Duda said that Article 5 of the North Atlantic Treaty was "binding," as shown by how NATO allies came to America’s aid following the terrorist attacks of September 11, 2001.
The Polish president told reporters: “Article 5 is very practical … The North Atlantic Treaty is binding and it’s not theoretical, it’s practical.”
Tanks for Ukraine
Duda reiterated Poland’s plan to support war-torn Ukraine with a company of German-made Leopard 2 main battle tanks.
He said: “We have decided to send Leopard tanks to Ukraine as part of a wider coalition with allies. Ukraine needs modern equipment … to repel the Russian assault.”
Tuesday’s talks between the Polish and Czech presidents focused on bilateral ties, trans-border and regional cooperation, and security issues amid Russia’s invasion of Ukraine, officials said.
Late on Tuesday, multiple news outlets reported that the German government had decided to send Leopard tanks to Ukraine and allow other countries such as Poland to do the same.
As Leopard 2 tanks are made in Germany, Berlin’s permission is required for their re-export, officials have said.
Some of Ukraine's allies, including Poland, Finland and Sweden, had urged Germany to allow them to support Kyiv with Leopard 2 tanks, according to officials.
Meanwhile, the United States was expected to announce a decision on Wednesday to send its Abrams tanks to Ukraine, according to news reports.
Wednesday is day 336 of Russia’s war against Ukraine.
Source: IAR, PAP, prezydent.pl
Click on the audio player above for a report by Radio Poland's Michał Owczarek.