Poland, the Czech Republic, Hungary and Slovakia must work together in order to be influential in the European Union, the Polish president said after meeting his Czech counterpart in Warsaw.
Czech President Miloš Zeman and Polish President Andrzej Duda met for talks on Thursday about the future of the European Union after Zeman was sworn in for a second five-year term.
Zeman said the four countries which make up the Visegrad Group should strive for unity.
Duda said Poland and the Czech Republic would try to ensure continued high spending on investment and development under the European Union's 2021-2027 budget.
Poland is the largest recipient of European Union cohesion funds under the 2014-2020 budget but may receive some EUR 8-10 billion less under the proposed new budget.
The two presidents also discussed bilateral trade.
Duda said that the Czech Republic is Poland's second biggest export destination after Germany, with bilateral trade worth more than EUR 20 billion.
Duda said he hoped trade would develop in the automotive and defence sectors.