Spain's Prime Minister Mariano Rajoy says he has asked Catalan leader Carles Puigdemont to confirm whether or not he has declared independence, reports BBC.
He said this was necessary before the Spanish government could take other measures.
On Tuesday Puigdemont signed a declaration of independence, but halted implementation to allow negotiations.
Rajoy accused Puigdemont of creating "deliberate confusion" and said he wanted to restore "certainty".
The prime minister said the Spanish government would base its response on the answer it was given, including any measures it might take invoking a constitutional clause allowing for direct rule.
Article 155 of the Spanish constitution would allow Rajoy to suspend Catalonia's autonomy and impose direct rule from Madrid.
"This call - ahead of any of the measures that the government may adopt under Article 155 of our constitution - seeks to offer citizens the clarity and security that a question of such importance requires," Rajoy said.