Updated

German Chancellor Angela Merkel says European Union treaties guarantee the integrity and sovereignty of member nations, a diplomatic warning to separatist politicians in the Spanish region of Catalonia who plan to declare independence if they win a majority in upcoming local elections.

Asked at a news conference Tuesday with Spanish Prime Minister Mariano Rajoy if such a declaration would mean Catalonia's expulsion from the EU, Merkel would only say she shared Rajoy's stance and that international and national laws must be obeyed.

Catalonia's ruling Convergence party and other political and civil groups are running joint candidates and say they will unilaterally leave Spain if they obtain a majority in elections Sept. 27.

Madrid has ruled out any possibility of secession.