Rafal Trzaskowski, the mayor of Warsaw, has announced the establishment of an association of local governments on Thursday. Trzaskowski announced the move at a joint press conference in Warsaw with the mayors of Poznan, Opole, Bialystok, and the mayor-elect of the south-eastern city of Rzeszow. All Poland's major cities are opposition controlled, and they have become something of a thorn in the flesh of Poland's conservative government for a number of years. "Our aim is victory in parliamentary elections and defeating (ruling Law and Justice party - PAP) PiS," Trzaskowski said.