MADRID (AP) — Regional authorities in Catalonia deny news reports that U.S. anti-terrorism officials warned them of a planned attack in Barcelona, but admit receiving tips of possible attacks from other sources they deemed not very credible.

Catalan regional interior chief Joaquim Forn said Thursday regional police were not warned by the CIA or the National Counterterrorism Center, adding that such warnings would be made through state channels.

Barcelona-based El Periodico newspaper said the U.S. sent the warning May 25 to regional police, specifically mentioning Las Ramblas.

A van attack Aug. 17 on Las Ramblas killed 14 people. One other person was stabbed to death by the Barcelona attacker as he fled. Another attack in nearby Cambrils left 1 dead.

The U.S. embassy in Madrid said it could not comment on intelligence issues.