WARSAW (Reuters) - Polish Prime Minister Donald Tusk said on Saturday that Poland is starting work on further strengthening the entire eastern border, as the country faces what he called a growing "hybrid war" in illegal migration from Belarus.

Poland plans to bolster security along its eastern borders amid threats from Belarus and Russia, Prime Minister Donald Tusk said on Saturday.

Warsaw has also, for several years, accused Belarus of deliberately pushing migrants into Poland in order to pressure the EU over sanctions, a charge Belarus has denied.

Poland’s defense minister says his country is strengthening the metal barrier along its border with Belarus to deter illegal migration.

The curious case of an official in Poland’s previous nationalist government, who defected to Belarus, is proving to be a boon for Prime Minister Donald Tusk a month before European Parliament elections.

Tusk accused Belarus, an ally of Russia, of escalating a hybrid war against the West by incentivizing migrants to attempt entry into the EU. He pledged that Poland would spare no expense in enhancing its border security.