BRUSSELS — The ousted leader of Catalonia recently addressed a rally of separatist voters in a packed theater in the Catalan city of Igualada. He was not among his separatist supporters, but spoke via satellite from hundreds of miles away: in Belgium.

The long-distance campaign for re-election by the leader, Carles Puigdemont, highlights the unorthodox circumstances surrounding the Dec. 21 Catalan elections. They were convened by Prime Minister Mariano Rajoy of Spain to defeat a secessionist drive by Mr. Puigdemont and other separatist officials and to return the restive region to what the Spanish leader called “normality.”

“These are absolutely abnormal conditions” for an election campaign, Mr. Puigdemont said in an interview in Brussels, the Belgian capital. “I consider it very difficult to take part now in any debate on an equal footing” with rival candidates.

Mr. Puigdemont surfaced in Brussels in October and is refusing to return to Spain to stand trial on charges of rebellion. Mr. Rajoy had ousted his administration and dissolved the Catalan Parliament, using emergency constitutional powers to stop separatist lawmakers who had unilaterally declared independence.