MADRID - Catalan separatist party Junts introduced a measure in Spain's lower house on Monday urging Prime Minister Pedro Sanchez to submit to a motion of confidence, further straining the fragile minority government that relies on Junts backing to pass laws.

Junts - which locked horns with Madrid over a failed 2017 bid to declare Catalonia's independence - has proven a thorny partner for the Socialist-led executive, arguing Madrid is chronically under-investing in the northeastern region and reneging on some of the concessions it had promised.

"(Sanchez) counted on our votes to become prime minister - let him show his face," Junts leader Carles Puigdemont, who lives in self-imposed exile in Belgium, told a news conference.

"We're proposing a question of confidence because those of us who put our trust in him feel that he hasn't honoured that gesture."

Constitutionally, only the prime minister can decide whether to ask for the lower house's confidence through a simple majority. The procedure is distinct from a motion of no confidence, which in Spain requires the party filing it to present an alternative candidate for the premiership and secure an absolute majority.

In conversation with foreign correspondents in Madrid, Sanchez said he had "neither intention nor need" to submit to a confidence vote, which has only been held twice since the country's return to democracy in 1978.

However, Junts' initiative will be debated in early 2025, with the conservative People's Party and far-right Vox expected to back it, ensuring its passage.

Still, Sanchez - who does not have to call elections until 2027 - may choose to ignore parliament's non-binding request.

Puigdemont warned that if Sanchez were to do this, his party's confidence in the government would be broken, implying Junts would withdraw all suppo...