Catalan regional president Quim Torra issued an ultimatum to Spanish Prime Minister Pedro Sanchez on Tuesday over the wealthy northeastern region's future.
Torra indicated he could deny Sanchez the votes he needs to approve the national budget in Spain's parliament unless the government proposes by next month an independence referendum in Catalonia.
Failure to get a budget passed could spell the end of Sanchez's four-month-old administration and bring a snap election.
Torra, a leading secessionist, said in a speech in Barcelona that Catalan separatist parties won't back Sanchez in parliament if their demand for a vote on self-determination is not met.
"Our patience ... is not endless," Torra said. "If a proposal to exercise self-determination in an agreed, binding and internationally recognized way is not on the table by November, the independence movement cannot guarantee for Mr. Sanchez any kind of stability in parliament."
The ultimatum was aimed directly at Sanchez's growing predicament over his center-left Socialist government's spending plans for 2019.
The minority government holds just 84 of the 350 seats in the country's lower house. That means it is relying on the expected support of other parties, including those supporting Catalan secession, to pass its state budget.
