Pedro Sanchez spoke in Spain's southern city of Granada where he is hosting more than 40 European leaders rallying around Ukraine on Thursday, and an EU summit on Friday.
Friday's talks will focus on how to prepare the 27-nation EU for adding new members one day, including possibly Ukraine, and on how to respond to increased arrivals of refugees and migrants from the Middle East and Africa so far this year.
"We cannot let some areas of our country, such as the south, the Canary or Balearic Islands face and assume all this irregular migration without solidarity," Sanchez told reporters.
In the days before the talks, Spain, Italy and Germany have raised concerns about increasing arrivals, while eastern EU countries said they were tightening their borders to curb irregular immigration.
Sea arrivals to Spain from Senegal and other African countries increased by a fifth so far this year compared with the last, with more than 3,500 reaching Canary Islands last month amid milder weather and calmer seas, according to official statistics.
Italy's island of Lampedusa has also seen more irregular immigration this year, posing a political headache for Prime Minister Giorgia Meloni who won power in 2022 on promises of reducing arrivals.
Speaking in Granada, Meloni welcomed a deal between the 27 on Wednesday on sharing out the task of hosting and providing for new arrivals, an agreement that puts the bloc closer to overhauling its defunct asylum and migration system after a decade of bitter internal disputes.
TUNISIA
The bloc tightened its asylum laws and external borders after more than a million people - mostly refugees fleeing the war in Syria - reached its shores across the Mediterranean in 2015.
Anti-immigrant rhetoric mounted, even as the overall number of arrivals started shrinking considerably after that year. The bloc's top migration official last week put irregular immigration in the EU at 250,000 people so far this year. U.N. data shows fewer than 195,500 such arrivals.
The EU cut a deal with Turkey in 2016 and, more recently, with Tunisia, offering money and other assistance in exchange for governments there keeping a tighter lid on departures for Europe from their soil.
Tunisian President Kais Saied this week balked at the EU's offer of sending only 127 million euros ($133.5 mln) as a first instalment of a promised 1 billion euros.
EU officials said Saied was bargaining for more money amid an acute economic crisis in Tunisia, which is also locked in negotiations with the International Monetary Fund on a $1.9 billion loan to stave off the risk of a default.
Some in the EU criticised the deal with Tunisia as not doing enough to confront human rights abuses there, but Meloni said the bloc needed to seek more such pacts with North African countries.
Both her and Sanchez face criticism from rivals at home over their handling of migration, with harsh rhetoric intensifying ahead of European Parliament elections next June across the EU.
Fernando Clavijo, regional leader of the Canary Islands and a critic of the Spanish premier, dismissed the bloc's new migration policies at an event in Madrid on Thursday: "It's smoke and mirrors... They are in an election campaign because they have elections next year."
He named Germany, which introduced border checks to push back against increased irregular immigration from EU neighbours, and Poland, which refuses to host asylum-seekers from the Middle East or Africa to help countries like Spain, and said:
"Europe does not have a migration policy. The response to the phenomenon differs from country to country. Germany has one, Poland has another, Italy has another... Solidarity - where?", he said.
($1 = 0.9510 euros)
(Reporting by Gabriela Baczynska, Inti Landauro, Federico Maccioni, Aislinn Laing, Emma Pinedo, David Latona; Editing by Andrew Heavens)
By Gabriela Baczynska and Inti Landauro
