Warsaw - Conservative Lech Kaczynski was sworn in as Poland's president on Friday, assuming office after winning elections on a promise to make a clean break with the post-communist past and build a stronger, honest state.

Kaczynski's inauguration completes a swing to the right in the biggest new European Union member after the conservatives, led by his identical twin brother, Jaroslaw, also won parliamentary elections in September.

Kaczynski, 56, succeeds two-term incumbent, leftist Aleksander Kwasniewski.

The former Warsaw mayor remains a virtual unknown on the international stage. His election agenda combined traditionalist Catholic values with support for more state intervention in the economy and promises to improve the lot of the poor.