EU and Russian diplomats failed last week to coordinate the start of talks to replace the current Friendship and Cooperation Agreement, which expires in 2007, over Warsaw's ultimatum that Moscow first sign the Energy Charter with Europe and lift an embargo on Polish agricultural exports to Russia.
Talks on the agreement were to be launched at a Russia-European Union summit in Helsinki this Friday.
"If we agreed [to give way to Russia], it would mean that Russia, which is a major partner of the EU, could regard Poland as if it were not a European Union member," Jaroslaw Kaczynski said.
"Poland must protect its national interests," Kaczynski said.
Russia banned agricultural imports from Poland last year, citing health risks. But Warsaw said the embargo was in retaliation for Poland's support of the "orange revolution" in Ukraine in late 2004, when Western-leaning political forces came to power in the former Soviet state.
Markos Kyprianou, European Commissioner for Health and Consumer Protection, confirmed Monday that the former Communist-bloc state, which joined the EU in 2004, is unlikely to lift its veto by November 24.
He met with Polish Agriculture Minister Andrzej Lepper earlier in the day, who said Poland will not backtrack on its decision until Russia "gives a clear signal" that it will lift the embargo.