By Belén Carreño

MADRID (Reuters) -The leader of Spain's far-right Vox party announced late on Thursday he was pulling out of five regional government coalitions with the centre-right People's Party (PP) due to disagreements on migration policy.

The PP, which runs five regions including Valencia in partnership with Vox, on Wednesday backed a plan by Spain's central Socialist-run government to move around 400 under-18 migrants from the Canary Islands to the peninsula.

"The vice-presidents - in the regional governments - will announce their resignation and Vox will go into opposition," Santiago Abascal told journalists in a televised speech that lasted less than five minutes. He didn't take questions.

Not all Vox politicians followed their leader's instructions. On Friday morning, several councillors - the equivalent of regional ministers - in some of the coalition governments in the five regions refused to resign and left the party.

"Vox no longer represents my ideals or my fighting spirit," Ignacio Higuero, the environment minister of the southwestern region of Extremadura, said.

Spain's Socialist Prime Minister Pedro Sanchez celebrated the disorder in the ranks of the far-right party. "Today is a great day for Spain, Spain is a better country today," he told a news conference at a NATO summit in Washington.

Around 19,000 migrants, mostly from West Africa, arrived in the Canary Islands, off sub-Saharan Africa, in the first six months of 2024, a 167% increase from the same period a year earlier, according to government figures.

Around 6,000 unaccompanied minors among the migrants are currently on the archipelago and the central government has urged other Spanish regions to take in arrivals as it seeks to ease pressure on infrastructure.

The PP regional leaders affected by Vox's decision to pull out of coalitions in the five regions - the Balearic Islands, Extremadura, Aragon, Valencia and Murcia - said they will try to govern alone. Without Vox's support, these regions may not be able to approve a budget for 2025.

"Our party has principles and political maturity," the PP's national leader Alberto Nunez Feijoo told a press conference." The PP will always respect the law and fulfil its responsibilities."

Founded in 2013, Vox has become the third-largest party in Spain. However, while far-right parties saw a strong performance in this year's European Parliament elections, Vox's share of the vote in Spain was lower than in national elections in July 2023.

Under-18s who migrate alone to Spain are entitled to government protection and aid under Spanish law.

In 2022, Spain offered more funding to regions that volunteered to host unaccompanied young migrants. But, to date, few conservative-run regions have accepted more than a handful.

The central government says it is now considering making transfers compulsory once the numbers in reception centres in the Canaries reach a certain level.

(Reporting by Belén Carreño, editing by Pietro Lombardi, Aislinn Laing and Susan Fenton)