BRUSSELS - The European Union in May registered a steep rise of illegal entries from the Western Balkans into the 27-nation bloc, the EU border agency Frontex said on Monday.

"In May, the number of irregular migrants detected in the region more than doubled to 12,088," Frontex said in a statement, adding that the main countries of origin were Syria and Afghanistan.

Between January and May 2022, Frontex recorded 40,675 illegal crossings overall on the Western Balkans route, nearly three times the figure from the same period the previous year.

The Western Balkans route thus accounted for almost half the total number of the 86,420 illegal crossings at the EU's borders in the period, Frontex said.

The agency did not give a reason for the surge but added that most of the people detected had been in the Western Balkans for some time before seeking to enter the EU.

People fleeing the war in Ukraine are not included in these figures, Frontex said.

The agency noted that according to its latest data more than 5.5 million Ukrainians have entered the EU since Russia launched its invasion in February, an action that Moscow describes as "special military operation".

(Reporting by Sabine Siebold, editing by Charlotte Van Campenhout)